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Protsak, T. V., and O. S. Zabrods`ka. "PATHOPHYSIOLOGICAL BASES ABOUT HIRS�HSPRUNG`S DISEASE (MORBUS HIRS�HSPRUNG)." Bulletin of Problems Biology and Medicine 1.2, no. 144 (2018): 42. http://dx.doi.org/10.29254/2077-4214-2018-1-2-143-42-45.
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Wang, Likun, Changyong Cao, and Pubu Ciren. "Assessing NOAA-16 HIRS Radiance Accuracy Using Simultaneous Nadir Overpass Observations from AIRS." Journal of Atmospheric and Oceanic Technology 24, no. 9 (September 1, 2007): 1546–61. http://dx.doi.org/10.1175/jtech2073.1.
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Abstract The High-Resolution Infrared Radiation Sounder (HIRS) has been carried on NOAA satellites for more than two decades, and the HIRS data have been widely used for geophysical retrievals, climate studies, and radiance assimilation for numerical weather prediction models. However, given the legacy of the filter-wheel radiometer originally designed in the 1970s, the HIRS measurement accuracy is neither well documented nor well understood, despite the importance of this information for data users, instrument manufacturers, and calibration scientists. The advent of hyperspectral sounders, such as the Atmospheric Infrared Sounder (AIRS), and intersatellite calibration techniques makes it possible to independently assess the accuracy of the HIRS radiances. This study independently assesses the data quality and calibration accuracy of HIRS by comparing the radiances between HIRS on NOAA-16 and AIRS on Aqua with simultaneous nadir overpass (SNO) observations for the year 2004. The results suggest that the HIRS radiometric bias relative to the AIRS-convolved HIRS radiance is on the order of ∼0.5 K, except channel 16, which has a bias of 0.8 K. For all eight spectrally overlapped channels, the observations by HIRS are warmer than the corresponding AIRS-convolved HIRS channel. Other than channel 16, the biases are temperature dependent. The root causes of the bias can be traced to a combination of the HIRS blackbody emissivity, nonlinearity, and spectral uncertainties. This study further demonstrates the utility of high-spectral-resolution radiance measurements for high-accuracy assessments of broadband radiometer calibration with the SNO observations.
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Gierens, Klaus, Kostas Eleftheratos, and Robert Sausen. "Intercalibration between HIRS/2 and HIRS/3 channel 12 based on physical considerations." Atmospheric Measurement Techniques 11, no. 2 (February 16, 2018): 939–48. http://dx.doi.org/10.5194/amt-11-939-2018.
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Abstract. High-resolution Infrared Radiation Sounder (HIRS) brightness temperatures at channel 12 (T12) can be used to assess the water vapour content of the upper troposphere. The transition from HIRS/2 to HIRS/3 in 1999 involved a shift in the central wavelength of channel 12 from 6.7 to 6.5 µm, causing a discontinuity in the time series of T12. To understand the impact of this change in the measured brightness temperatures, we have performed radiative transfer calculations for channel 12 of HIRS/2 and HIRS/3 instruments, using a large set of radiosonde profiles of temperature and relative humidity from three different sites. Other possible changes within the instrument, apart from the changed spectral response function, have been assumed to be of minor importance, and in fact, it was necessary to assume as a working hypothesis that the spectral and radiometric calibration of the two instruments did not change during the relatively short period of their common operation. For each radiosonde profile we performed two radiative transfer calculations, one using the HIRS/2 channel response function of NOAA 14 and one using the HIRS/3 channel response function of NOAA 15, resulting in negative differences of T12 (denoted as ΔT12:=T12/15-T12/14) ranging between −12 and −2 K. Inspection of individual profiles for large, medium and small values of ΔT12 pointed to the role of the mid-tropospheric humidity. This guided us to investigate the relation between ΔT12 and the channel 11 brightness temperatures which are typically used to detect signals from the mid-troposphere. This allowed us to construct a correction for the HIRS/3 T12, which leads to a pseudo-channel 12 brightness temperature as if a HIRS/2 instrument had measured it. By applying this correction we find an excellent agreement between the original HIRS/2 T12 and the HIRS/3 data inferred from the correction method with R=0.986. Upper-tropospheric humidity (UTH) derived from the pseudo HIRS/2 T12 data compared well with that calculated from intersatellite-calibrated data, providing independent justification for using the two intercalibrated time series (HIRS/2 and HIRS/3) as a continuous HIRS time series for long-term UTH analyses.
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Lee, Hai-Tien, Arnold Gruber, Robert G. Ellingson, and Istvan Laszlo. "Development of the HIRS Outgoing Longwave Radiation Climate Dataset." Journal of Atmospheric and Oceanic Technology 24, no. 12 (December 1, 2007): 2029–47. http://dx.doi.org/10.1175/2007jtecha989.1.
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Abstract The Advanced Very High Resolution Radiometer (AVHRR) outgoing longwave radiation (OLR) product, which NOAA has been operationally generating since 1979, is a very long data record that has been used in many applications, yet past studies have shown its limitations and several algorithm-related deficiencies. Ellingson et al. have developed the multispectral algorithm that largely improved the accuracy of the narrowband-estimated OLR as well as eliminated the problems in AVHRR. NOAA has been generating High Resolution Infrared Radiation Sounder (HIRS) OLR operationally since September 1998. In recognition of the need for a continuous and long OLR data record that would be consistent with the earth radiation budget broadband measurements in the National Polar-orbiting Operational Environmental Satellite System (NPOESS) era, and to provide a climate data record for global change studies, a vigorous reprocessing of the HIRS radiance for OLR derivation is necessary. This paper describes the development of the new HIRS OLR climate dataset. The HIRS level 1b data from the entire Television and Infrared Observation Satellite N-series (TIROS-N) satellites have been assembled. A new radiance calibration procedure was applied to obtain more accurate and consistent HIRS radiance measurements. The regression coefficients of the HIRS OLR algorithm for all satellites were rederived from calculations using an improved radiative transfer model. Intersatellite calibrations were performed to remove possible discontinuity in the HIRS OLR product from different satellites. A set of global monthly diurnal models was constructed consistent with the HIRS OLR retrievals to reduce the temporal sampling errors and to alleviate an orbital-drift-induced artificial trend. These steps significantly improved the accuracy, continuity, and uniformity of the HIRS monthly mean OLR time series. As a result, the HIRS OLR shows a comparable stability as in the Earth Radiation Budget Satellite (ERBS) nonscanner OLR measurements. HIRS OLR has superb agreement with the broadband observations from Earth Radiation Budget Experiment (ERBE) and Clouds and the Earth’s Radiant Energy System (CERES) in the ENSO-monitoring regions. It shows compatible ENSO-monitoring capability with the AVHRR OLR. Globally, HIRS OLR agrees with CERES with an accuracy to within 2 W m−2 and a precision of about 4 W m−2. The correlation coefficient between HIRS and CERES global monthly mean is 0.997. Regionally, HIRS OLR agrees with CERES to within 3 W m−2 with precisions better than 3 W m−2 in most places. HIRS OLR could be used for constructing climatology for applications that plan to use NPOESS ERBS and previously used AVHRR OLR observations. The HIRS monthly mean OLR data have high accuracy and precision with respect to the broadband observations of ERBE and CERES. It can be used as an independent validation data source. The uniformity and continuity of HIRS OLR time series suggest that it could be used as a reliable transfer reference for the discontinuous broadband measurements from ERBE, CERES, and ERBS.
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Gierens, Klaus, and Kostas Eleftheratos. "Technical note: On the intercalibration of HIRS channel 12 brightness temperatures following the transition from HIRS 2 to HIRS 3/4 for ice saturation studies." Atmospheric Measurement Techniques 10, no. 2 (March 3, 2017): 681–93. http://dx.doi.org/10.5194/amt-10-681-2017.
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Abstract. In the present study we explore the capability of the intercalibrated HIRS brightness temperature data at channel 12 (the HIRS water vapour channel; T12) to reproduce ice supersaturation in the upper troposphere during the period 1979–2014. Focus is given on the transition from the HIRS 2 to the HIRS 3 instrument in the year 1999, which involved a shift of the central wavelength in channel 12 from 6.7 to 6.5 µm. It is shown that this shift produced a discontinuity in the time series of low T12 values ( < 235 K) and associated cases of high upper-tropospheric humidity with respect to ice (UTHi > 70 %) in the year 1999 which prevented us from maintaining a continuous, long-term time series of ice saturation throughout the whole record (1979–2014). We show that additional corrections are required to the low T12 values in order to bring HIRS 3 levels down to HIRS 2 levels. The new corrections are based on the cumulative distribution functions of T12 from NOAA 14 and 15 satellites (that is, when the transition from HIRS 2 to HIRS 3 occurred). By applying these corrections to the low T12 values we show that the discontinuity in the time series caused by the transition of HIRS 2 to HIRS 3 is not apparent anymore when it comes to calculating extreme UTHi cases. We come up with a new time series for values found at the low tail of the T12 distribution, which can be further exploited for analyses of ice saturation and supersaturation cases. The validity of the new method with respect to typical intercalibration methods such as regression-based methods is presented and discussed.
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Menzel, W. Paul, Richard A. Frey, Eva E. Borbas, Bryan A. Baum, Geoff Cureton, and Nick Bearson. "Reprocessing of HIRS Satellite Measurements from 1980 to 2015: Development toward a Consistent Decadal Cloud Record." Journal of Applied Meteorology and Climatology 55, no. 11 (November 2016): 2397–410. http://dx.doi.org/10.1175/jamc-d-16-0129.1.
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AbstractThis paper presents the cloud-parameter data records derived from High Resolution Infrared Radiation Sounder (HIRS) measurements from 1980 through 2015 on the NOAA and MetOp polar-orbiting platforms. Over this time period, the HIRS sensor has been flown on 16 satellites from TIROS-N through NOAA-19 and MetOp-A and MetOp-B, forming a 35-yr cloud data record. Intercalibration of the Infrared Advanced Sounding Interferometer (IASI) and HIRS on MetOp-A has created confidence in the onboard calibration of this HIRS as a reference for others. A recent effort to improve the understanding of IR-channel response functions of earlier HIRS sensor radiance measurements using simultaneous nadir overpasses has produced a more consistent sensor-to-sensor calibration record. Incorporation of a cloud mask from the higher-spatial-resolution Advanced Very High Resolution Radiometer (AVHRR) improves the subpixel cloud detection within the HIRS measurements. Cloud-top pressure and effective emissivity (εf, or cloud emissivity multiplied by cloud fraction) are derived using the 15-μm spectral bands in the carbon dioxide (CO2) absorption band and implementing the CO2-slicing technique; the approach is robust for high semitransparent clouds but weak for low clouds with little thermal contrast from clear-sky radiances. This paper documents the effort to incorporate the recalibration of the HIRS sensors, notes the improvements to the cloud algorithm, and presents the HIRS cloud data record from 1980 to 2015. The reprocessed HIRS cloud data record reports clouds in 76.5% of the observations, and 36.1% of the observations find high clouds.
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Burgdorf, Martin J., Thomas G. Müller, Stefan A. Buehler, Marc Prange, and Manfred Brath. "Characterization of the High-Resolution Infrared Radiation Sounder Using Lunar Observations." Remote Sensing 12, no. 9 (May 7, 2020): 1488. http://dx.doi.org/10.3390/rs12091488.
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The High-Resolution Infrared Radiation Sounder (HIRS) has been operational since 1975 on different satellites. In spite of this long utilization period, the available information about some of its basic properties is incomplete or contradictory. We have approached this problem by analyzing intrusions of the Moon in the deep space view of HIRS/2 through HIRS/4. With this method we found: (1) The diameters of the field of view of HIRS/2, HIRS/3, and HIRS/4 have the relative proportions of 1.4 ° to 1.3 ° to 0.7 ° with all channels; (2) the co-registration differs by up to 0.031 ° among the long-wave and by up to 0.015 ° among the shortwave spectral channels in the along-track direction; (3) the photometric calibration is consistent within 0.7% or less for channels 2–7 (1.2% for HIRS/2), similar values were found for channels 13–16; (4) the non-linearity of the short-wavelength channels is negligible; and (5) the contribution of reflected sunlight to the flux in the short-wavelength channels can be determined in good approximation, if the emissivity of the surface is known.
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Peng, Ge, Lei Shi, Steve T. Stegall, Jessica L. Matthews, and Christopher W. Fairall. "An Evaluation of HIRS Near-Surface Air Temperature Product in the Arctic with SHEBA Data." Journal of Atmospheric and Oceanic Technology 33, no. 3 (March 2016): 453–60. http://dx.doi.org/10.1175/jtech-d-15-0217.1.
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AbstractThe accuracy of cloud-screened 2-m air temperatures derived from the intersatellite-calibrated brightness temperatures based on the High Resolution Infrared Radiation Sounder (HIRS) measurements on board the National Oceanic and Atmospheric Administration (NOAA) Polar-Orbiting Operational Environmental Satellite (POES) series is evaluated by comparing HIRS air temperatures to 1-yr quality-controlled measurements collected during the Surface Heat Budget of the Arctic Ocean (SHEBA) project (October 1997–September 1998). The mean error between collocated HIRS and SHEBA 2-m air temperature is found to be on the order of 1°C, with a slight sensitivity to spatial and temporal radii for collocation. The HIRS temperatures capture well the temporal variability of SHEBA temperatures, with cross-correlation coefficients higher than 0.93, all significant at the 99.9% confidence level. More than 87% of SHEBA temperature variance can be explained by linear regression of collocated HIRS temperatures. The analysis found a strong dependency of mean temperature errors on cloud conditions observed during SHEBA, indicating that availability of an accurate cloud mask in the region is essential to further improve the quality of HIRS near-surface air temperature products. This evaluation establishes a baseline of accuracy of HIRS temperature retrievals, providing users with information on uncertainty sources and estimates. It is a first step toward development of a new long-term 2-m air temperature product in the Arctic that utilizes intersatellite-calibrated remote sensing data from the HIRS instrument.
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Gierens, K., K. Eleftheratos, and L. Shi. "Technical Note: 30 years of HIRS data of upper tropospheric humidity." Atmospheric Chemistry and Physics Discussions 14, no. 5 (March 5, 2014): 5871–92. http://dx.doi.org/10.5194/acpd-14-5871-2014.
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Abstract. We use 30 years of intercalibrated HIRS data to produce a 30 year data set of upper tropospheric humidity with respect to ice (UTHi). Since the required brightness temperatures (channels 12 and 6, T12 and T6) are intercalibrated to different versions of the HIRS sensors (HIRS/2 and HIRS/4) it is necessary to convert the channel 6 brightness temperatures which are intercalibrated to HIRS/4 into equivalent brightness temperatures intercalibrated to HIRS/2, which is achieved using a linear regression. Using the new regression coefficients we produce daily files of UTHi, T12 and T6, for each NOAA satellite and METOP-A, which carry the HIRS instrument. From this we calculate daily and monthly means in 2.5° × 2.5° resolution for the northern mid-latitude zone 30 to 60° N. As a first application we calculate decadal means of UTHi and the brightness temperatures for the two decades 1980–1989 and 2000–2009. We find that the humidity mainly increased from the 1980s to the 2000s and that this increase is highly statistically significant in large regions of the considered mid-latitude belt. The main reason for this result and its statistical significance is the corresponding increase of the T12 variance. Changes of the mean brightness temperatures are less significant.
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Wylie, Donald, Edwin Eloranta, James D. Spinhirne, and Steven P. Palm. "A Comparison of Cloud Cover Statistics from the GLAS Lidar with HIRS." Journal of Climate 20, no. 19 (October 1, 2007): 4968–81. http://dx.doi.org/10.1175/jcli4269.1.
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Abstract The cloud dataset from the Geoscience Laser Altimeter System (GLAS) lidar on the Ice, Cloud, and Land Elevation Satellite (ICESat) spacecraft is compared to the cloud analysis of the Wisconsin NOAA High Resolution Infrared Radiation Sounder (HIRS) Pathfinder. This is the first global lidar dataset from a spacecraft of extended duration that can be compared to the HIRS climatology. It provides an excellent source of cloud information because it is more sensitive to clouds that are difficult to detect, namely, thin cirrus and small boundary layer clouds. The second GLAS data collection period from 1 October to 16 November 2003 was used for this comparison, and a companion dataset of the same days were analyzed with HIRS. GLAS reported cloud cover of 0.70 while HIRS reported slightly higher cloud cover of 0.75 for this period. The locations where HIRS overreported cloud cover were mainly in the Arctic and Antarctic Oceans and parts of the Tropics. GLAS also confirms that upper-tropospheric clouds (above 6.6 km) cover about 0.33 of the earth, similar to the reports from HIRS data. Generally, the altitude of the cloud tops reported by GLAS is, on average, higher than HIRS by 0.4 to 4.5 km. The largest differences were found in the Tropics, over 4 km, while in midlatitudes average differences ranged from 0.4 to 2 km. Part of this difference in averaged cloud heights comes from GLAS finding more high cloud coverage in the Tropics, 5% on average but >13% in some areas, which weights its cloud top average more toward the high clouds than the HIRS. The diffuse character of the upper parts of high clouds over tropical oceans is also a cause for the difference in reported cloud heights. Statistics on cloud sizes also were computed from GLAS data to estimate the errors in cloud cover reported by HIRS from its 20-km field-of-view (FOV) size. Smaller clouds are very common with one-half of all clouds being <41 km in horizontal size. But, clouds <41 km cover only 5% of the earth. Cloud coverage is dominated by larger clouds with one-half of the coverage coming from clouds >1000 km. GLAS cloud size statistics also show that HIRS possibly overreports some cloud forms by 2%–3%. Looking at groups of GLAS data 21 km long to simulate the HIRS FOV, the authors found that ∼5% are partially filled with cloud. Since HIRS does not account for the part of the FOV without cloud, it will overreport the coverage of these clouds. However, low-altitude and optically thin clouds will not be reported by HIRS if they are so small that they do not affect the upwelling radiation in the HIRS FOV enough to trigger the threshold for cloud detection. These errors are partially offing.
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MacKenzie, Ian A., Simon F. B. Tett, and Anders V. Lindfors. "Climate Model–Simulated Diurnal Cycles in HIRS Clear-Sky Brightness Temperatures." Journal of Climate 25, no. 17 (April 13, 2012): 5845–63. http://dx.doi.org/10.1175/jcli-d-11-00552.1.
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Abstract Clear-sky brightness temperature measurements from the High-Resolution Infrared Radiation Sounder (HIRS) are simulated with two climate models via a radiative transfer code. The models are sampled along the HIRS orbit paths to derive diurnal climatologies of simulated brightness temperature analogous to an existing climatology based on HIRS observations. Simulated and observed climatologies are compared to assess model performance and the robustness of the observed climatology. Over land, there is good agreement between simulations and observations, with particularly high consistency for the tropospheric temperature channels. Diurnal cycles in the middle- and upper-tropospheric water vapor channels are weak in both simulations and observations, but the simulated diurnal brightness temperature ranges are smaller than are observed with different phase and there are also intermodel differences. Over sea, the absence of diurnal variability in the models’ sea surface temperatures causes an underestimate of the small diurnal cycles measured in the troposphere. The simulated and observed climatologies imply similar diurnal sampling biases in the HIRS record for the tropospheric temperature channels, but for the upper-tropospheric water vapor channel, differences in the contributions of the 24- and 12-hourly diurnal harmonics lead to differences in the implied bias. Comparison of diurnal cycles derived from HIRS-like and full model sampling suggests that the HIRS measurements are sufficient to fully constrain the diurnal behavior. Overall, the results suggest that recent climate models well represent the major processes driving the diurnal behavior of clear-sky brightness temperature in the HIRS channels. This encourages further studies of observed and simulated climate trends over the HIRS era.
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Gierens, K., K. Eleftheratos, and L. Shi. "Technical Note: 30 years of HIRS data of upper tropospheric humidity." Atmospheric Chemistry and Physics 14, no. 14 (July 28, 2014): 7533–41. http://dx.doi.org/10.5194/acp-14-7533-2014.
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Abstract. We use 30 years of intercalibrated HIRS (High-Resolution Infrared Radiation Sounder) data to produce a 30-year data set of upper tropospheric humidity with respect to ice (UTHi). Since the required brightness temperatures (channels 12 and 6, T12 and T6) are intercalibrated to different versions of the HIRS sensors (HIRS/2 and HIRS/4) it is necessary to convert the channel 6 brightness temperatures which are intercalibrated to HIRS/4 into equivalent brightness temperatures intercalibrated to HIRS/2, which is achieved using a linear regression. Using the new regression coefficients we produce daily files of UTHi, T12 and T6, for each NOAA satellite and METOP-A (Meteorological Operational Satellite Programme), which carry the HIRS instrument. From this we calculate daily and monthly means in 2.5° × 2.5° resolution for the northern midlatitude zone 30–60° N. As a first application we calculate decadal means of UTHi and the brightness temperatures for the two decades 1980–1989 and 2000–2009. We find that the humidity mainly increased from the 1980s to the 2000s and that this increase is highly statistically significant in large regions of the considered midlatitude belt. The main reason for this result and its statistical significance is the corresponding increase of the T12 variance. Changes of the mean brightness temperatures are less significant.
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Cao, Changyong, Kenneth Jarva, and Pubu Ciren. "An Improved Algorithm for the Operational Calibration of the High-Resolution Infrared Radiation Sounder." Journal of Atmospheric and Oceanic Technology 24, no. 2 (February 1, 2007): 169–81. http://dx.doi.org/10.1175/jtech2037.1.
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Abstract Radiance data from the High-Resolution Infrared Radiation Sounder (HIRS) have been used routinely in both direct radiance assimilation for numerical weather prediction and climate change detection studies. The operational HIRS calibration algorithm is critical for producing accurate radiance to meet the user’s needs, and it has significant impacts on products at all levels. Since the HIRS does not calibrate every scan line, the calibration coefficients between calibration cycles have to be interpolated based on a number of assumptions. In the more than 25-yr history of operational HIRS calibration, several interpolation methods have been used and, unfortunately, depending on which method is used, these algorithms can produce HIRS level 1b radiance data with significant differences. By analyzing the relationship between the instrument self-emission and gain change during filter temperature fluctuations, in this paper a significant flaw in the previous operational calibration algorithm (version 3) is identified. This caused calibration errors greater than 0.5 K and periodically degraded the HIRS radiance data quality of NOAA-15, -16, and -17 between 1998 and 2005. A new HIRS calibration algorithm (version 4) is introduced to improve the calibration accuracy, along with better indicators for instrument noise in the level 1b data. The new algorithm has been validated in parallel tests before it became operational at NOAA/National Environmental Satellite Data and Information Service (NESDIS). Test results show that significant improvements in calibration accuracy can be achieved especially for NOAA-15/HIRS. Several areas of further calibration improvements are also identified. The new algorithm has been used for all operational satellites at NOAA/NESDIS since 28 April 2005.
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Schreck, Carl, Hai-Tien Lee, and Kenneth Knapp. "HIRS Outgoing Longwave Radiation—Daily Climate Data Record: Application toward Identifying Tropical Subseasonal Variability." Remote Sensing 10, no. 9 (August 21, 2018): 1325. http://dx.doi.org/10.3390/rs10091325.
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This study describes the development of a new globally gridded climate data record (CDR) for daily outgoing longwave radiation (OLR) using the High-Resolution Infrared Radiation Sounder (HIRS) sensor. The new product, hereafter referred to as HIRS OLR, has several differences and advantages over the widely-used daily OLR dataset derived from the Advanced Very High-Resolution Radiometer (AVHRR) sensor on the same NOAA Polar Operational Environmental Satellites (POES), hereafter AVHRR OLR. As a CDR, HIRS OLR has been intersatellite-calibrated to provide the most homogeneous record possible. AVHRR OLR only used the daytime and nighttime overpasses from a single satellite at a time, which creates some challenges for resolving the large diurnal cycle of OLR. HIRS OLR leverages all available overpasses and then calibrates geostationary estimates of OLR to represent that cycle more faithfully. HIRS also has more spectral channels, including those for measuring water vapor, which provides a more accurate measure of OLR. This difference is particularly relevant for large-scale convective systems such as the El Niño–Southern Oscillation and the Madden–Julian Oscillation, whereby the HIRS OLR can better identify the subtropical variability between the tropical convection and the extratropical teleconnections.
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Holl, Gerrit, Jonathan P. D. Mittaz, and Christopher J. Merchant. "Error Correlations in High-Resolution Infrared Radiation Sounder (HIRS) Radiances." Remote Sensing 11, no. 11 (June 3, 2019): 1337. http://dx.doi.org/10.3390/rs11111337.
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The High-resolution Infrared Radiation Sounder (HIRS) has been flown on 17 polar-orbiting satellites between the late 1970s and the present day. HIRS applications require accurate characterisation of uncertainties and inter-channel error correlations, which has so far been lacking. Here, we calculate error correlation matrices by accumulating count deviations for sequential sets of calibration measurements, and then correlating deviations between channels (for a fixed view) or views (for a fixed channel). The inter-channel error covariance is usually assumed to be diagonal, but we show that large error correlations, both positive and negative, exist between channels and between views close in time. We show that correlated error exists for all HIRS and that the degree of correlation varies markedly on both short and long timescales. Error correlations in excess of 0.5 are not unusual. Correlations between calibration observations taken sequentially in time arise from periodic error affecting both calibration and Earth counts. A Fourier spectral analysis shows that, for some HIRS instruments, this instrumental effect dominates at some or all spatial frequencies. These findings are significant for application of HIRS data in various applications, and related information will be made available as part of an upcoming Fundamental Climate Data Record covering all HIRS channels and satellites.
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Jackson, Darren L., and Brian J. Soden. "Detection and Correction of Diurnal Sampling Bias in HIRS/2 Brightness Temperatures." Journal of Atmospheric and Oceanic Technology 24, no. 8 (August 1, 2007): 1425–38. http://dx.doi.org/10.1175/jtech2062.1.
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Abstract Diurnal sampling biases arise in the High-Resolution Infrared Radiation Sounder (HIRS) satellite observations because some of the NOAA polar-orbiting satellites drift significantly from their original local observation time. Such bias adversely affects interpretation of these data for climate studies. Twenty-six years of HIRS/2 radiance satellite data (1979–2004) were examined by creating monthly mean gridded data that categorize the observations by local observing time through averaging ascending and descending orbits separately. Corresponding HIRS/2 simulated radiance data from the Geophysical Fluid Dynamics Laboratory (GFDL) climate model were constructed using HIRS/2 satellite sampling and were found to accurately represent the diurnal sampling bias. Correction of the HIRS/2 observations from the observed diurnal sampling bias was using the model simulations of HIRS brightness temperatures to adjust the observed brightness temperatures to the model daily mean. The diurnal bias was found to vary with channel, surface type, latitude, satellite, and cloud cover, but showed little dependence on satellite scan angle. Diurnal bias is most pronounced for ascending orbit observations of the afternoon [1400 local solar time (LST)] satellites with 60°N to 60°S domain averaged brightness temperatures variations up to 0.78 K yr−1. Lower tropospheric temperature and water vapor channels contained the largest bias, and biases over land were more than twice as large as those over the ocean. Brightness temperature adjustments of up to 10 K were needed in the most extreme situations.
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Chedzey, Helen, W. Paul Menzel, and Mervyn Lynch. "Changes in HIRS Detection of Cloud over Australia from 1985 to 2001." Remote Sensing 13, no. 5 (March 1, 2021): 917. http://dx.doi.org/10.3390/rs13050917.
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A long-term archive of cloud properties (cloud top pressure, CTP; and cloud effective emissivity, ε) determined from High-resolution Infrared Radiation Sounder (HIRS) data is investigated for evidence of regional cloud cover change. In the 17 years between 1985 and 2001, different cloud types are analysed over the Australian region (10° S–45° S, 105° E–160° E) and areas of change in total cloud frequency examined. Total cloud frequency change over the Australian region between two adjacent eight-year time periods (1994 to 2001 minus 1985 to 1992) shows the largest increases (ranges between 6% and 12%) of average HIRS total cloud cover occurring over the offshore regions to the northwest and northeast of the continent. Over land, the largest reduction of average HIRS total cloud frequency is in the southwestern region of Australia (between 2% and 8%). Through central Australia, there is a 2% to 7% increase in average HIRS total cloud frequency when comparing these eight-year periods. This paper examines the regional cloud changes in 17 years over Australia that are embedded in global cloud statistics. Examining total HIRS cloud cover frequency over Australia and comparing two different eight-year time periods, has highlighted notable areas of average change. Preliminary reporting of satellite-derived HIRS cloud products and Global Precipitation Climatology Project (GPCP) rainfall products during La Niña seasons between 1985 and 2001 has also been undertaken.
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Matthews, Jessica, and Lei Shi. "Intercomparisons of Long-Term Atmospheric Temperature and Humidity Profile Retrievals." Remote Sensing 11, no. 7 (April 9, 2019): 853. http://dx.doi.org/10.3390/rs11070853.
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This study builds upon a framework to develop a climate data record of temperature and humidity profiles from high-resolution infrared radiation sounder (HIRS) clear-sky measurements. The resultant time series is a unique, long-term dataset (1978–2017). To validate this long-term dataset, evaluation of the stability of the intersatellite time series is coupled with intercomparisons with independent observation platforms as available in more recent years. Eleven pairs of satellites carrying the HIRS instrument with time periods that overlap are examined. Correlation coefficients were calculated for the retrieval of each atmospheric pressure level and for each satellite pair. More than 90% of the cases examining both temperature and humidity have correlation coefficients greater than 0.7. Very high correlation is demonstrated at the surface and two meter levels for both temperature (>0.99) and specific humidity (>0.93). For the period of 2006–2017, intercomparisons are performed with four independent observations platforms: radiosonde (RS92), constellation observing system for meteorology ionosphere and climate (COSMIC), global climate observing system (GCOS) reference upper-air network (GRUAN), and infrared atmospheric sounding interferometer (IASI). Very close matching of surface and two meter temperatures over a wide domain of values is depicted in all presented intercomparisons: intersatellite matches of HIRS retrievals, HIRS vs. GRUAN, and HIRS vs. IASI.
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Shi, Lei, Ge Peng, and John J. Bates. "Surface Air Temperature and Humidity from Intersatellite-Calibrated HIRS Measurements in High Latitudes." Journal of Atmospheric and Oceanic Technology 29, no. 1 (January 1, 2012): 3–13. http://dx.doi.org/10.1175/jtech-d-11-00024.1.
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Abstract High-latitude ocean surface air temperature and humidity derived from intersatellite-calibrated High-Resolution Infrared Radiation Sounder (HIRS) measurements are examined. A neural network approach is used to develop retrieval algorithms. HIRS simultaneous nadir overpass observations from high latitudes are used to intercalibrate observations from different satellites. Investigation shows that if HIRS observations were not intercalibrated, then it could lead to intersatellite biases of 1°C in the air temperature and 1–2 g kg−1 in the specific humidity for high-latitude ocean surface retrievals. Using a full year of measurements from a high-latitude moored buoy site as ground truth, the instantaneous (matched within a half-hour) root-mean-square (RMS) errors of HIRS retrievals are 1.50°C for air temperature and 0.86 g kg−1 for specific humidity. Compared to a large set of operational moored and drifting buoys in both northern and southern oceans greater than 50° latitude, the retrieval instantaneous RMS errors are within 2.6°C for air temperature and 1.4 g kg−1 for specific humidity. Compared to 5 yr of International Maritime Meteorological Archive in situ data, the HIRS specific humidity retrievals show less than 0.5 g kg−1 of differences over the majority of northern high-latitude open oceans.
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Cao, Changyong, Mitch Goldberg, and Likun Wang. "Spectral Bias Estimation of Historical HIRS Using IASI Observations for Improved Fundamental Climate Data Records." Journal of Atmospheric and Oceanic Technology 26, no. 7 (July 1, 2009): 1378–87. http://dx.doi.org/10.1175/2009jtecha1235.1.
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Abstract A prerequisite for climate change detection from satellites is that the measurements from a series of historical satellites must be consistent and ideally made traceable to the International System of Units (SI). Unfortunately, this requirement is not met for the 14 High Resolution Infrared Radiation Sounders (HIRS) on the historical NOAA satellites, because the instrument was developed for weather forecasts and lacks accuracy and consistency across satellites. It is well known that for HIRS, differences in the spectral response functions (SRF) between instruments and their prelaunch measurement uncertainties often lead to observations of the atmosphere at different altitudes. As a result of the atmospheric lapse rate, they both can introduce significant intersatellite biases. The SRF-dependent biases are further mixed with other effects such as the diurnal cycle because of observation time differences and orbital drifts, on board calibration, and algorithm issues. In this study, the Infrared Atmospheric Sounding Interferometer (IASI) observations are used to calculate the radiances for the 14 Television Infrared Observation Satellite series N (TIROS-N; to MetOp-A) HIRS instruments in different climate regimes and seasons to separate the SRF-induced intersatellite biases from other factors. It is found that the calculated radiance ratio (a bias indicator) using IASI observations for the HIRS satellite pairs forms bell-shaped curves that vary with the HIRS model and channel as well as climate regimes. This suggests that a bias found in the polar regions at the Simultaneous Nadir Overpass (SNO) cannot be blindly used for bias correction globally; instead, the IASI/HIRS spectral bias bell curves should be used as a complement to more fully address the biases. These bell curves also serve as lookup charts for separating the bias due to true SRF differences from that caused by SRF prelaunch measurement errors to resolve the inconsistency, which sheds new light on reprocessing and reanalysis in generating fundamental climate data records from HIRS.
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Chung, Eui-Seok, and Brian J. Soden. "Investigating the Influence of Carbon Dioxide and the Stratosphere on the Long-Term Tropospheric Temperature Monitoring from HIRS." Journal of Applied Meteorology and Climatology 49, no. 9 (September 1, 2010): 1927–37. http://dx.doi.org/10.1175/2010jamc2486.1.
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Abstract Contrary to a midtropospheric warming trend detected from Microwave Sounding Unit (MSU) measurements, High-Resolution Infrared Radiation Sounder (HIRS) temperature (15 μm) channels, sensitive to the thermal emission from the troposphere, produce distinct cooling trends for the period 1980–99. This apparent discrepancy in the tropospheric temperature trend is investigated through radiative transfer simulations using Geophysical Fluid Dynamics Laboratory climate model output and the profiles of the standard model atmospheres. Radiative simulations with time-invariant carbon dioxide concentration throughout the entire analysis period produce trends that are qualitatively similar to that obtained from the MSU observations, implying that the observed cooling trends of the HIRS temperature channels are attributable to increased carbon dioxide concentration over the 20-yr period. Additional simulations with the observed time-varying concentration of carbon dioxide confirm this basic result. Whereas temperature fluctuations dominate variability on monthly to interannual time scales, carbon dioxide changes dominate the decadal trends in both the observations and model simulations. Further simulations examined the sensitivity of the brightness temperature change with respect to the changes in tropospheric and stratospheric temperature. These calculations indicate that the influences of stratospheric temperature on the measured radiances are greater for the HIRS temperature channels relative to the MSU midtropospheric channel. These results highlight the contributions of time-varying carbon dioxide concentrations and stratospheric temperature to the HIRS 15-μm (temperature channel) radiance record and underscore the importance of accurately accounting for these changes when using HIRS measurements for long-term monitoring.
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Frey, Richard A., and W. Paul Menzel. "Observed HIRS and MODIS High-Cloud Frequencies in the 2000s." Journal of Applied Meteorology and Climatology 58, no. 11 (November 2019): 2469–78. http://dx.doi.org/10.1175/jamc-d-19-0060.1.
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AbstractThis paper compares the cloud parameter data records derived from High Resolution Infrared Radiation Sounder (HIRS) and Moderate Resolution Imaging Spectroradiometer (MODIS) measurements from the years 2003 through 2013. Cloud-top pressure (CTP) and effective emissivity (εf; cloud emissivity multiplied by cloud fraction) are derived using the 15-μm spectral bands in the CO2 absorption band and implementing the CO2-slicing technique; the approach is robust for high semitransparent clouds but weak for low clouds with little thermal contrast from clear-sky radiances. The high-cloud (HiCld; with CTP less than 440 hPa) seasonal cycles of HIRS and MODIS observations are found to be in sync, but the HIRS frequency of detection is about 10% higher than that of MODIS (which is attributed to a lower threshold for cloud detection in the HIRS CO2 bands). Differences are largest during nighttime and at the beginning of the time series (2003–06). Both show Northern Hemisphere (NH) and Southern Hemisphere (SH) seasonal HiClds are out of phase and both agree within 2% on NH–SH HiCld differences. During the summer, maximum HiCld frequency averages 5% more in the NH.
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Knapp, Kenneth R. "Calibration Assessment of ISCCP Geostationary Infrared Observations Using HIRS." Journal of Atmospheric and Oceanic Technology 25, no. 2 (February 1, 2008): 183–95. http://dx.doi.org/10.1175/2007jtecha910.1.
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Abstract Infrared window (∼11 μm) brightness temperatures from global geostationary meteorological instruments were calibrated using the High Resolution Infrared Radiation Sounder (HIRS) as an independent analysis of the satellite intercalibration performed by the International Satellite Cloud Climatology Project (ISCCP). Criteria for matching geostationary observations with HIRS from previous literature were inadequate to analyze a shift in calibration due to the limited range of resulting temperatures. The result was an inability to determine the impact of a calibration error on observations of cold clouds. To better understand the calibration error, a new set of matchup criteria that collected targets at all temperatures proportionately showed a significant shift in the ISCCP calibration. Using the new criteria, it became apparent that observations of cold temperatures were biased too cold. A correction based on these results removed the bias between the geostationary and HIRS observations.
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Wylie, Donald, Darren L. Jackson, W. Paul Menzel, and John J. Bates. "Trends in Global Cloud Cover in Two Decades of HIRS Observations." Journal of Climate 18, no. 15 (August 1, 2005): 3021–31. http://dx.doi.org/10.1175/jcli3461.1.
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Abstract The frequency of cloud detection and the frequency with which these clouds are found in the upper troposphere have been extracted from NOAA High Resolution Infrared Radiometer Sounder (HIRS) polar-orbiting satellite data from 1979 to 2001. The HIRS/2 sensor was flown on nine satellites from the Television Infrared Observation Satellite-Next Generation (TIROS-N) through NOAA-14, forming a 22-yr record. Carbon dioxide slicing was used to infer cloud amount and height. Trends in cloud cover and high-cloud frequency were found to be small in these data. High clouds show a small but statistically significant increase in the Tropics and the Northern Hemisphere. The HIRS analysis contrasts with the International Satellite Cloud Climatology Project (ISCCP), which shows a decrease in both total cloud cover and high clouds during most of this period.
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WYLIE, D., and W. MENZEL. "A cirrus cloud climatology from NOAA/HIRS." Global and Planetary Change 4, no. 1-3 (July 1991): 49–53. http://dx.doi.org/10.1016/0921-8181(91)90069-9.
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Lindfors, Anders V., Ian A. Mackenzie, Simon F. B. Tett, and Lei Shi. "Climatological Diurnal Cycles in Clear-Sky Brightness Temperatures from the High-Resolution Infrared Radiation Sounder (HIRS)." Journal of Atmospheric and Oceanic Technology 28, no. 10 (October 1, 2011): 1199–205. http://dx.doi.org/10.1175/jtech-d-11-00093.1.
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Abstract A climatology of the diurnal cycles of HIRS clear-sky brightness temperatures was developed based on measurements over the period 2002–07. This was done by fitting a Fourier series to monthly gridded brightness temperatures of HIRS channels 1–12. The results show a strong land–sea contrast with stronger diurnal cycles over land, and extending from the surface up to HIRS channel 6 or 5, with regional maxima over the subtropics. Over seas, the diurnal cycles are generally small and therefore challenging to detect. A Monte Carlo uncertainty analysis showed that more robust results are reached by aggregating the data zonally before applying the fit. The zonal fits indicate that small diurnal cycles do exist over sea. The results imply that for a long-lived satellite such as NOAA-14, drift in the overpass time can cause a diurnal sampling bias of more than 5 K for channel 8 (surface and lower troposphere).
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Cao, Changyong, Hui Xu, Jerry Sullivan, Larry McMillin, Pubu Ciren, and Yu-Tai Hou. "Intersatellite Radiance Biases for the High-Resolution Infrared Radiation Sounders (HIRS) on board NOAA-15, -16, and -17 from Simultaneous Nadir Observations." Journal of Atmospheric and Oceanic Technology 22, no. 4 (April 1, 2005): 381–95. http://dx.doi.org/10.1175/jtech1713.1.
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Abstract Intersatellite radiance comparisons for the 19 infrared channels of the High-Resolution Infrared Radiation Sounders (HIRS) on board NOAA-15, -16, and -17 are performed with simultaneous nadir observations at the orbital intersections of the satellites in the polar regions, where each pair of the HIRS views the same earth target within a few seconds. Analysis of such datasets from 2000 to 2003 reveals unambiguous intersatellite radiance differences as well as calibration anomalies. The results show that in general, the intersatellite relative biases are less than 0.5 K for most HIRS channels. The large biases in different channels differ in both magnitude and sign, and are likely to be caused by the differences and measurement uncertainties in the HIRS spectral response functions. The seasonal bias variation in the stratosphere channels is found to be highly correlated with the lapse rate factor approximated by the channel radiance differences. The method presented in this study works particularly well for channels sensing the stratosphere because of the relative spatial uniformity and stability of the stratosphere, for which the intercalibration accuracy and precision are mostly limited by the instrument noise. This method is simple and robust, and the results are highly repeatable and unambiguous. Intersatellite radiance calibration with this method is very useful for the on-orbit verification and monitoring of instrument performance, and is potentially useful for constructing long-term time series for climate studies.
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Staten, Paul W., Brian H. Kahn, Mathias M. Schreier, and Andrew K. Heidinger. "Subpixel Characterization of HIRS Spectral Radiances Using Cloud Properties from AVHRR." Journal of Atmospheric and Oceanic Technology 33, no. 7 (July 2016): 1519–38. http://dx.doi.org/10.1175/jtech-d-15-0187.1.
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AbstractThis paper describes a cloud type radiance record derived from NOAA polar-orbiting weather satellites using cloud properties retrieved from the Advanced Very High Resolution Radiometer (AVHRR) and spectral brightness temperatures (Tb) observed by the High Resolution Infrared Radiation Sounder (HIRS). The authors seek to produce a seamless, global-scale, long-term record of cloud type and Tb statistics intended to better characterize clouds from seasonal to decadal time scales. Herein, the methodology is described in which the cloud type statistics retrieved from AVHRR are interpolated onto each HIRS footprint using two cloud classification methods. This approach is tested over the northeast tropical and subtropical Pacific Ocean region, which contains a wide variety of cloud types during a significant ENSO variation from 2008 to 2009. It is shown that the Tb histograms sorted by cloud type are realistic for all HIRS channels. The magnitude of Tb biases among spatially coincident satellite intersections over the northeast Pacific is a function of cloud type and wavelength. While the sign of the bias can change, the magnitudes are generally small for NOAA-18 and NOAA-19, and NOAA-19 and MetOp-A intersections. The authors further show that the differences between calculated standard deviations of cloud-typed Tb well exceed intersatellite calibration uncertainties. The authors argue that consideration of higher-order statistical moments determined from spectral infrared observations may serve as a useful long-term measure of small-scale spatial changes, in particular cloud types over the HIRS–AVHRR observing record.
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Siemann, Amanda L., Gabriele Coccia, Ming Pan, and Eric F. Wood. "Development and Analysis of a Long-Term, Global, Terrestrial Land Surface Temperature Dataset Based on HIRS Satellite Retrievals." Journal of Climate 29, no. 10 (April 28, 2016): 3589–606. http://dx.doi.org/10.1175/jcli-d-15-0378.1.
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Abstract Land surface temperature (LST) is a critical state variable for surface energy exchanges as it is one of the controls on emitted radiation at Earth’s surface. LST also exerts an important control on turbulent fluxes through the temperature gradient between LST and air temperature. Although observations of surface energy balance components are widely accessible from in situ stations in most developed regions, these ground-based observations are not available in many underdeveloped regions. Satellite remote sensing measurements provide wider spatial coverage to derive LST over land and are used in this study to form a high-resolution, long-term LST data product. As selected by the Global Energy and Water Exchanges project (GEWEX) Data and Assessments Panel (GDAP) for development of internally consistent datasets, the High Resolution Infrared Radiation Sounder (HIRS) data are used for the primary satellite observations because of the data record length. The final HIRS-consistent, hourly, global, 0.5° resolution LST dataset for clear and cloudy conditions from 1979 to 2009 is developed through merging the National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis (CFSR) LST estimates with the HIRS retrievals using a Bayesian postprocessing procedure. The Baseline Surface Radiation Network (BSRN) observations are used to validate the HIRS retrievals, the CFSR LST estimates, and the final merged LST dataset. An intercomparison between the original retrievals and CFSR LST datasets, before and after merging, is also presented with an analysis of the datasets, including an error assessment of the final LST dataset.
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Zhang, Lei, Hongfei Zhou, Shaokun Bai, and Shaodan Li. "A benzene-bridged divanadium complex-early transition metal catalyst for alkene alkylarylation with PhI(O2CR)2via decarboxylation." Dalton Transactions 50, no. 9 (2021): 3201–6. http://dx.doi.org/10.1039/d0dt04295a.
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Miles, Georgina M., Richard Siddans, Roy G. Grainger, Alfred J. Prata, Bradford Fisher, and Nickolay Krotkov. "Retrieval of volcanic SO<sub>2</sub> from HIRS/2 using optimal estimation." Atmospheric Measurement Techniques 10, no. 7 (July 26, 2017): 2687–702. http://dx.doi.org/10.5194/amt-10-2687-2017.
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Abstract. We present an optimal-estimation (OE) retrieval scheme for stratospheric sulfur dioxide from the High-Resolution Infrared Radiation Sounder 2 (HIRS/2) instruments on the NOAA and MetOp platforms, an infrared radiometer that has been operational since 1979. This algorithm is an improvement upon a previous method based on channel brightness temperature differences, which demonstrated the potential for monitoring volcanic SO2 using HIRS/2. The Prata method is fast but of limited accuracy. This algorithm uses an optimal-estimation retrieval approach yielding increased accuracy for only moderate computational cost. This is principally achieved by fitting the column water vapour and accounting for its interference in the retrieval of SO2. A cloud and aerosol model is used to evaluate the sensitivity of the scheme to the presence of ash and water/ice cloud. This identifies that cloud or ash above 6 km limits the accuracy of the water vapour fit, increasing the error in the SO2 estimate. Cloud top height is also retrieved. The scheme is applied to a case study event, the 1991 eruption of Cerro Hudson in Chile. The total erupted mass of SO2 is estimated to be 2300 kT ± 600 kT. This confirms it as one of the largest events since the 1991 eruption of Pinatubo, and of comparable scale to the Northern Hemisphere eruption of Kasatochi in 2008. This retrieval method yields a minimum mass per unit area detection limit of 3 DU, which is slightly less than that for the Total Ozone Mapping Spectrometer (TOMS), the only other instrument capable of monitoring SO2 from 1979 to 1996. We show an initial comparison to TOMS for part of this eruption, with broadly consistent results. Operating in the infrared (IR), HIRS has the advantage of being able to measure both during the day and at night, and there have frequently been multiple HIRS instruments operated simultaneously for better than daily sampling. If applied to all data from the series of past and future HIRS instruments, this method presents the opportunity to produce a comprehensive and consistent volcanic SO2 time series spanning over 40 years.
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Shi, L., C. J. Schreck III, and V. O. John. "An improved HIRS upper tropospheric water vapor dataset and its correlations with major climate indices." Atmospheric Chemistry and Physics Discussions 12, no. 12 (December 21, 2012): 33411–42. http://dx.doi.org/10.5194/acpd-12-33411-2012.
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Abstract. A new version of the upper tropospheric water vapor dataset is developed using intersatellite calibrated all-sky High-Resolution Infrared Radiation Sounder (HIRS) data. In this dataset, the majority of pixels that do not affect the water vapor processing in the upper troposphere are retained. Compared to the previous version that was based on column-clear-sky data, the new version has a much better daily spatial coverage and provides a better representation of the atmosphere. The HIRS observation patterns are compared to microwave sounder measurements. The differences between the two types of sounders are examined, and the analysis displays that the differences vary with respect to brightness temperature. An examination of the correlations of the HIRS upper tropospheric water vapor with major climate indices shows that the dataset is well correlated with climate indices especially in cold seasons. The selected climate indices track climate variation signals covering regions from the tropics to the poles. The correlation analysis shows the potential of using the upper tropospheric water vapor dataset together with a suite of many atmospheric variables to monitor regional climate changes and locate global teleconnection patterns.
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Shi, L., C. J. Schreck III, and V. O. John. "HIRS channel 12 brightness temperature dataset and its correlations with major climate indices." Atmospheric Chemistry and Physics 13, no. 14 (July 23, 2013): 6907–20. http://dx.doi.org/10.5194/acp-13-6907-2013.
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Abstract. A new version of the High-Resolution Infrared Radiation Sounder (HIRS) upper tropospheric water vapor channel (channel 12) brightness temperature dataset is developed using intersatellite calibrated data. In this dataset, only those pixels affected by upper tropospheric clouds are discarded. Compared to the previous version that was based on column-clear-sky data, the new version has much better daily spatial coverage. The HIRS observation patterns are compared to microwave sounder measurements. The differences between the two types of sounders vary with respect to brightness temperature with larger differences for higher (dry) values. Correlations between the HIRS upper tropospheric water vapor channel brightness temperatures and several major climate indices show strong signals during cold seasons. The selected climate indices track climate variation signals covering regions from the tropics to the poles. Qualitatively, moist signals are correlated with troughs and ascending branches of the circulation, while dry signals occur with ridges and descent. These correlations show the potential of using the upper tropospheric water vapor channel brightness temperature dataset together with a suite of many atmospheric variables to monitor regional climate changes and locate global teleconnection patterns.
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Wylie, Donald P., and W. Paul Menzel. "Eight Years of High Cloud Statistics Using HIRS." Journal of Climate 12, no. 1 (January 1, 1999): 170–84. http://dx.doi.org/10.1175/1520-0442-12.1.170.
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Abstract Over the last 8 yr frequency and location of cloud observations have been compiled using multispectral High Resolution Infrared Radiation Sounder (HIRS) data from the National Oceanic and Atmospheric Administration polar-orbiting satellites; this work is an extension of the 4-yr dataset reported by D. Wylie et al. The CO2 slicing algorithm applied to the HIRS data exhibits a higher sensitivity to semitransparent cirrus clouds than the cloud algorithm used by the International Satellite Cloud Climatology Project; the threshold for cloud detection appears to require visible optical depths (τvis) greater than 0.1. The geographical distributions of clouds in the 8-yr dataset are nearly the same as those reported from 4 yr of data. The detection of upper-tropospheric clouds occurs most often in the intertropical convergence zone and midlatitude storm belts with lower concentrations in subtropical deserts and oceanic subtropical highs. The areas of concentrated cloud cover exhibit latitudinal movement with the seasons as in other cloud datasets. HIRS finds clear sky in 25%, opaque cloud in 32%, and semitransparent cloud in 43% of all its observations. The effective emissivity of the all semitransparent clouds (τvis < 6) ranges from 0.2 to 0.6 with an average value of about 0.5. Time trends are reexamined in detail. A possible cirrus increase in 1991 reported by Wylie and coauthors in 1994 is found to be diminished upon reinspection. The revised 8-yr record has indications of an increase in high clouds in the northern midlatitudes (0.5% yr−1) but little change elsewhere. The seasonal cycle of cloud cover in the Southern Hemisphere becomes very noticeable in 1993.
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Turner, Emma C., and Simon F. B. Tett. "Using longwave HIRS radiances to test climate models." Climate Dynamics 43, no. 3-4 (October 26, 2013): 1103–27. http://dx.doi.org/10.1007/s00382-013-1959-6.
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Marco, Maria L., Jennifer Legac, and Steven E. Lindow. "Conditional Survival as a Selection Strategy To Identify Plant-Inducible Genes of Pseudomonas syringae." Applied and Environmental Microbiology 69, no. 10 (October 2003): 5793–801. http://dx.doi.org/10.1128/aem.69.10.5793-5801.2003.
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ABSTRACT A novel strategy termed habitat-inducible rescue of survival (HIRS) was developed to identify genes of Pseudomonas syringae that are induced during growth on bean leaves. This strategy is based on the complementation of metXW, two cotranscribed genes that are necessary for methionine biosynthesis and required for survival of P. syringae on bean leaves exposed to conditions of low humidity. We constructed a promoter trap vector, pTrap, containing a promoterless version of the wild-type P. syringae metXW genes. Only with an active promoter fused to metXW on pTrap did this plasmid restore methionine prototrophy to the P. syringae metXW mutant B7MX89 and survival of this strain on bean leaves. To test this method, a partial library of P. syringae genomic DNA was constructed in pTrap and a total of 1,400 B7MX89 pTrap clones were subjected to HIRS selection on bean leaves. This resulted in the enrichment of five clones, each with a unique RsaI restriction pattern of their DNA insert. Sequence analysis of these clones revealed those P. syringae genes for which putative plant-inducible activity could be assigned. Promoter activity experiments with a gfp reporter gene revealed that these plant-inducible gene promoters had very low levels of expression in minimal medium. Based on green fluorescent protein fluorescence levels, it appears that many P. syringae genes have relatively low expression levels and that the metXW HIRS strategy is a sensitive method to detect weakly expressed P. syringae genes that are active on plants. Furthermore, we found that protected sites on the leaf surface provided a higher level of enrichment for P. syringae expressing metXW than exposed sites. Thus, the metXW HIRS strategy should lead to the identification of P. syringae genes that are expressed primarily in these areas on the leaf.
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Zhang, Lei, Yin Wang, Yunhui Yang, Ping Zhang, and Congyang Wang. "Rhenium-catalyzed alkylarylation of alkenes with PhI(O2CR)2via decarboxylation to access indolinones and dihydroquinolinones." Organic Chemistry Frontiers 7, no. 20 (2020): 3234–41. http://dx.doi.org/10.1039/d0qo00953a.
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Rhenium-catalyzed alkylarylation of alkenes with hypervalent iodine(iii) reagents (HIRs) via decarboxylation to access various 3,3-disubstituted indolinones and trans-3,4-dihydroquinolinones is described.
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Hariroh, Ulya. "Aktualisasi Nilai Hirs dan Amanah terhadap Perilaku Mahasiswa PGMI Fakultas Tarbiyah IPMAFA." Dawuh Guru: Jurnal Pendidikan MI/SD 1, no. 2 (August 28, 2021): 177–92. http://dx.doi.org/10.35878/guru.v1i2.291.
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Nilai Dasar Shalih Akram (NDSA) merupakan nilai-nilai pesantren yang menjadi landasan pengembangan bagi Institut Pesantren Mathali’ul Falah (IPMAFA) Pati. NDSA dengan 9 nilai + 1 harus diaktualisasikan dalam kehidupan kampus, termasuk bagi mahasiswa. Penelitian ini bertujuan menjelaskan bagaimana aktualisasi nilai Hirs dan Amanah (bagian dari NDSA) terhadap perilaku mahasiswa PGMI Fakultas Tarbiyah IPMAFA. Penelitian diskriptif dengan pendekatan kualitatif ini menggunakan wawancara mendalam, dokumentasi, dan penelusuran online untuk mengumpulkan data. Selanjutnya dilakukan analisis interaktif dengna teorinya Miles dan Huberman. Hasil penelitian menunjukkan bahwa aktualisasi nilai hirs dan amanah dalam konsep NDSA terhadap perilaku mahasiswa PGMI Fakultas Tarbiyah IPMAFA sudah diupayakan dengan ikhtiyar dari berbagai pihak. Adapun langkah-langkah aktualisasinya yakni dengan adanya keteladanan, kedisplinan, pembiasaan, serta program integrasi dan internalisasi.
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Gierens, Klaus, and Kostas Eleftheratos. "On the interpretation of upper-tropospheric humidity based on a second-order retrieval from infrared radiances." Atmospheric Chemistry and Physics 19, no. 6 (March 22, 2019): 3733–46. http://dx.doi.org/10.5194/acp-19-3733-2019.
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Abstract. We present a novel retrieval for upper-tropospheric humidity (UTH) from High-resolution Infrared Radiation Sounder (HIRS) channel 12 radiances that successfully bridges the wavelength change from 6.7 to 6.5 µm that occurred from HIRS/2 on National Oceanic and Atmospheric Administration satellite NOAA-14 to HIRS/3 on satellite NOAA-15. The jump in average brightness temperature (in the water vapour channel; T12) that this change had caused (about −7 K) could be fixed with a statistical inter-calibration method (Shi and Bates, 2011). Unfortunately, the retrieval of UTHi (upper-tropospheric humidity with respect to ice) based on the inter-calibrated data was not satisfying at the high tail of the distribution of UTHi. Attempts to construct a better inter-calibration in the low T12 range (equivalent to the high UTHi range) were either not successful (Gierens et al., 2018) or required additional statistically determined corrections to the measured brightness temperatures (Gierens and Eleftheratos, 2017). The new method presented here is based on the original one (Soden and Bretherton, 1993; Stephens et al., 1996; Jackson and Bates, 2001), but it extends linearisations in the formulation of water vapour saturation pressure and in the temperature dependence of the Planck function to second order. To achieve the second-order formulation we derive the retrieval from the beginning, and we find that the most influential ingredient is the use of different optical constants for the two involved channel wavelengths (6.7 and 6.5 µm). The result of adapting the optical constant is an almost perfect match between UTH data measured by HIRS/2 on NOAA-14 and HIRS/3 on NOAA-15 on 1004 common days of operation. The method is applied to both UTH and UTHi. For each case retrieval coefficients are derived. We present a number of test applications, e.g. on computed brightness temperatures based on high-resolution radiosonde profiles, on the brightness temperatures measured by the satellites on the mentioned 1004 common days of operation. Further, we present time series of the occurrence frequency of high UTHi cases, and we show the overall probability distribution of UTHi. The two latter applications expose indications of moistening of the upper troposphere over the last 35 years. Finally, we discuss the significance of UTH. We state that UTH algorithms cannot be judged for their correctness or incorrectness, since there is no true UTH. Instead, UTH algorithms should fulfill a number of usefulness postulates, which we suggest and discuss.
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Borbas, Eva E., and Paul W. Menzel. "Observed HIRS and Aqua MODIS Thermal Infrared Moisture Determinations in the 2000s." Remote Sensing 13, no. 3 (January 31, 2021): 502. http://dx.doi.org/10.3390/rs13030502.
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This paper compares the tropospheric moisture data records derived from High-resolution Infrared Radiation Sounder (HIRS) and Moderate Resolution Imaging Spectro-radiometer (MODIS) measurements from the years 2003 through 2013. Total Precipitable Water Vapor (TPW) and Upper Tropospheric Precipitable Water Vapor (UTPW) are derived using the infrared spectral bands in the CO2 and H2O absorption bands as well as in the atmospheric windows. Retrieval of TPW and UTPW uses a statistical regression algorithm performed using clear sky radiances (and Brightness Temperatures) measured over land and ocean for both day and night. The TPW and UTPW seasonal cycles of HIRS and MODIS observations are found to be in synchronization with zonal mean values for one degree latitude bands within 2.0 mm and 0.07 mm, respectively.
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Kottayil, Ajil, Stefan A. Buehler, Viju O. John, Larry M. Miloshevich, M. Milz, and G. Holl. "On the Importance of Vaisala RS92 Radiosonde Humidity Corrections for a Better Agreement between Measured and Modeled Satellite Radiances." Journal of Atmospheric and Oceanic Technology 29, no. 2 (February 1, 2012): 248–59. http://dx.doi.org/10.1175/jtech-d-11-00080.1.
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Abstract A study has been carried out to assess the importance of radiosonde corrections in improving the agreement between satellite and radiosonde measurements of upper-tropospheric humidity. Infrared [High Resolution Infrared Radiation Sounder (HIRS)-12] and microwave [Advanced Microwave Sounding Unit (AMSU)-18] measurements from the NOAA-17 satellite were used for this purpose. The agreement was assessed by comparing the satellite measurements against simulated measurements using collocated radiosonde profiles of the Atmospheric Radiation Measurement (ARM) Program undertaken at tropical and midlatitude sites. The Atmospheric Radiative Transfer Simulator (ARTS) was used to simulate the satellite radiances. The comparisons have been done under clear-sky conditions, separately for daytime and nighttime soundings. Only Vaisala RS92 radiosonde sensors were used and an empirical correction (EC) was applied to the radiosonde measurements. The EC includes correction for mean calibration bias and for solar radiation error, and it removes radiosonde bias relative to three instruments of known accuracy. For the nighttime dataset, the EC significantly reduces the bias from 0.63 to −0.10 K in AMSU-18 and from 1.26 to 0.35 K in HIRS-12. The EC has an even greater impact on the daytime dataset with a bias reduction from 2.38 to 0.28 K in AMSU-18 and from 2.51 to 0.59 K in HIRS-12. The present study promises a more accurate approach in future radiosonde-based studies in the upper troposphere.
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Saba, Wesam Emad, Salwa M. Beheiry, Ghassan Abu-Lebdeh, and Mustafa S. AL-Tekreeti. "A Holistic Intersection Rating System (HIRS)—A Novel Methodology to Measure the Holistic Operational Performance of Signalized Urban Intersections." Smart Cities 4, no. 3 (July 19, 2021): 1018–38. http://dx.doi.org/10.3390/smartcities4030054.
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Signalized urban intersections are key components of urban transportation networks. They are traditionally viewed and designed as primarily motorized traffic facilities, and thus their physical and operational designs have traditionally aimed at maximizing traffic throughput subject to constraints dictated by vehicular safety requirements and pedestrian crossing needs. Seen from a holistic viewpoint, urban intersections are hubs or effective centers of community activities of which traffic flow is only one. Those hubs have direct and indirect impacts on the overlapping traffic functionalities, the environment, public health, community wellbeing, and the local economy. This study proposes a new rating system, the Holistic Intersection Rating System (HIRS), aimed at appraising signalized intersections from a more inclusive viewpoint. This appraisal covers traffic functionality, sustainability, and public health and community wellbeing. This rating system can be used as a guide to conceive, plan, or design new intersections or revamp existing ones. HIRS rates signalized urban intersections based on the level of use of relevant enabling technologies, and the physical and operational designs that allow those intersections to operate holistically, thus leading to a more human-centric and sustainable operational performance. HIRS was validated using a panel of experts in construction, transportation, and public health. The Relative Importance Index (RII) method was used to weigh the HIRS features. The rating system was piloted on a sample of 20 intersections in different cities in the UAE. The results revealed glaring gaps in services to or the consideration of pedestrians, cyclists, and nearby households. The sample intersections scored a mean of 32% on the public health and community wellbeing section, 37% on the pedestrian subsection, and 15% on the cyclist subsection. Such relatively low scores serve as indicators of areas for improvements, and if mapped to their specific features and their relative weights, specific physical and operations designs and technology integration can be identified as actionable items for inclusion in plans and/or designs.
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Wylie, Donald P., W. Paul Menzel, Harold M. Woolf, and Kathleen I. Strabala. "Four Years of Global Cirrus Cloud Statistics Using HIRS." Journal of Climate 7, no. 12 (December 1994): 1972–86. http://dx.doi.org/10.1175/1520-0442(1994)007<1972:fyogcc>2.0.co;2.
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Shi, Lei, John J. Bates, and Changyong Cao. "Scene Radiance–Dependent Intersatellite Biases of HIRS Longwave Channels." Journal of Atmospheric and Oceanic Technology 25, no. 12 (December 1, 2008): 2219–29. http://dx.doi.org/10.1175/2008jtecha1058.1.
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Abstract Measurements from the simultaneous nadir overpass (SNO) observations of the High Resolution Infrared Radiation Sounder (HIRS) are examined. The SNOs are the measurements taken at the orbital intersections of each pair of satellites viewing the same Earth target within a few seconds at high latitudes. The dataset includes satellites from NOAA-6 through NOAA-17 from 1981 to 2004. The authors found that for many channels, intersatellite biases vary significantly with respect to scene radiances. For a number of these channels, the change of the intersatellite bias within a channel can be larger than 1 mW (m2 sr cm−1)−1, which is approximately 1 K in brightness temperature, across the channel scene radiance ranges. Many of the channels with large variations of intersatellite biases are the tropospheric sounding channels centered along the sharp slope of the transmission line. These channels are particularly sensitive to the difference in spectral response functions from satellite to satellite. This radiance-dependency feature of the biases is an important factor to consider when performing intersatellite calibrations.
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Chen, Ruiyue, Changyong Cao, and W. Paul Menzel. "Intersatellite calibration of NOAA HIRS CO2channels for climate studies." Journal of Geophysical Research: Atmospheres 118, no. 11 (June 6, 2013): 5190–203. http://dx.doi.org/10.1002/jgrd.50447.
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Baum, Bryan A., Bruce A. Wielicki, Patrick Minnis, and Lindsay Parker. "Cloud-Property Retrieval Using Merged HIRS and AVHRR Data." Journal of Applied Meteorology 31, no. 4 (April 1992): 351–69. http://dx.doi.org/10.1175/1520-0450(1992)031<0351:cprumh>2.0.co;2.
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Nelson, C. C., and D. T. Nguyen. "Comparison of Hirs’ Equation With Moody’s Equation for Determining Rotordynamic Coefficients of Annular Pressure Seals." Journal of Tribology 109, no. 1 (January 1, 1987): 144–48. http://dx.doi.org/10.1115/1.3261306.
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The rotordynamic coefficients of an incompressible-flow annular pressure seal were determined using a bulk-flow model in conjunction with two different friction factor relationships. The first, Hirs’ equation, assumes the friction factor is a function of Reynolds number only. The second, Moody’s equation, approximates Moody’s diagram and assumes the friction factor is a function of both Reynolds number and relative roughness. For each value of relative roughness, Hirs’ constants were determined so that both equations gave the same magnitude and slope of the friction factor. For smooth seals, both relationships give the same results. For rough seals (e/2H0 = 0.05) Moody’s equation predicts 44 percent greater direct stiffness, 35 percent greater cross-coupled stiffness, 19 percent smaller cross-coupled damping, 59 percent smaller cross-coupled inertia, and nominally the same direct damping and direct inertia.
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Goldberg, Mitchell D., and Larry M. McMillin. "Methodology for Deriving Deep-Layer Mean Temperatures from Combined Satellite Infrared and Microwave Observations." Journal of Climate 12, no. 1 (January 1, 1999): 5–20. http://dx.doi.org/10.1175/1520-0442-12.1.5.
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Abstract Deep-layer mean temperatures from Microwave Sounding Unit (MSU) observations have been used by scientists to study trends and interannual variations of tropospheric and lower-stratospheric temperature. The spatial resolution of MSU deep-layer mean temperatures is rather poor for studying trends in localized regions. A method is developed in which infrared observations from the High-resolution InfraRed Sounder (HIRS) is used in combination with MSU to derive deep-layer mean temperatures with improved vertical and horizontal resolution. Even though the relationship between infrared radiance and temperature is not linear, the layer associated with the mean temperature is shown to be well defined with a small airmass dependency that is similar to MSU’s airmass dependency. Preliminary validation of HIRS–MSU-derived layer mean temperatures with radiosonde layer mean temperatures show similar precision when compared to MSU-only derived temperatures.
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Stegall, Steve, and Lei Shi. "An Assessment of HIRS Surface Air Temperature with USCRN Data." Remote Sensing 8, no. 6 (June 8, 2016): 485. http://dx.doi.org/10.3390/rs8060485.
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TURNER, J., and H. ELLROTT. "High-latitude moisture structure determined from HIRS water vapour imagery." International Journal of Remote Sensing 13, no. 1 (January 1992): 81–95. http://dx.doi.org/10.1080/01431169208904027.
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