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1
Bradley, Stuart, and Alexander Strehz. "Corrections to sodar Doppler winds due to wind drift." Meteorologische Zeitschrift 24, no. 6 (November 5, 2015): 605–14. http://dx.doi.org/10.1127/metz/2014/0627.
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Douglass, Scott L., and J. Richard Weggel. "LABORATORY EXPERIMENTS ON THE INFLUENCE OF WIND ON NEARSHORE WAVE BREAKING." Coastal Engineering Proceedings 1, no. 21 (January 29, 1988): 46. http://dx.doi.org/10.9753/icce.v21.46.
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The influence of wind on nearshore breaking waves was investigated in a laboratory wave tank. Breaker location, geometry, and type depended upon the wind acting on the wave as it broke. Onshore winds tended to cause waves to break earlier, in deeper water, and to spill: offshore winds tended to cause waves to break later, in shallower water, and to plunge. A change in wind direction from offshore to onshore increased the surf zone width by up to 100%. Wind's effect was greatest for waves which were near the transition between breaker types in the absence of wind. For onshore winds, it was observed that microscale breaking can initiate spilling breaking by providing a perturbation on the crest of the underlying wave as it shoals.
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Wang, Weichen, Susan A. Kassin, S. M. Faber, David C. Koo, Emily C. Cunningham, Hassen M. Yesuf, Guillermo Barro, et al. "The Baltimore Oriole’s Nest: Cool Winds from the Inner and Outer Parts of a Star-forming Galaxy at z = 1.3." Astrophysical Journal 930, no. 2 (May 1, 2022): 146. http://dx.doi.org/10.3847/1538-4357/ac6592.
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Abstract Strong galactic winds are ubiquitous at z ≳ 1. However, it is not well-known where inside galaxies these winds are launched from. We study the cool winds (∼104 K) in two spatial regions of a massive galaxy at z = 1.3, which we nickname the “Baltimore Oriole’s Nest.” The galaxy has a stellar mass of 1010.3±0.3 M ⊙, is located on the star-forming main sequence, and has a morphology indicative of a recent merger. Gas kinematics indicate a dynamically complex system with velocity gradients ranging from 0 to 60 km s−1. The two regions studied are: a dust-reddened center (Central region), and a blue arc at 7 kpc from the center (Arc region). We measure the Fe ii and Mg ii absorption line profiles from deep Keck/DEIMOS spectra. Blueshifted wings up to 450 km s−1 are found for both regions. The Fe ii column densities of winds are 1014.7±0.2 cm−2 and 1014.6±0.2 cm−2 toward the Central and Arc regions, respectively. Our measurements suggest that the winds are most likely launched from both regions. The winds may be driven by the spatially extended star formation, the surface density of which is around 0.2 M ⊙ yr−1 · kpc−2 in both regions. The mass outflow rates are estimated to be 4 M ⊙ yr−1 and 3 M ⊙ yr−1 for the Central and Arc regions, with uncertainties of one order of magnitude or more. The findings of this work and a few previous studies suggest that the cool galactic winds at z ≳ 1 might be commonly launched from the entire spatial extents of their host galaxies, due to extended galaxy star formation.
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Ivanov, Millen M., Leonid N. Georgiev, T. S. Valchev, B. V. Efremova, and Svetozar A. Zhekov. "Some aspects of the spectral variability of WR 141." Symposium - International Astronomical Union 193 (1999): 71–72. http://dx.doi.org/10.1017/s0074180900205007.
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An analysis of the behaviour of the He II 5411 line wings is presented. The spectral classification of the companion is discussed on the basis of a simple geometric model of the colliding stellar winds zone.
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Acker, A., and Y. Grosdidier. "Wind Inhomogeneities in [WC] Central Stars: From Late-to Early-Type Nuclei." Symposium - International Astronomical Union 209 (2003): 245. http://dx.doi.org/10.1017/s0074180900208632.
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In Grosdidier et al. (2000, 2001), wind fluctuations were described for five [WC 8–10] stars. In this poster we present new results discussing the case of the hotter subtype [WO 4] (Grosdidier & Acker 2002). Specifically, we concentrate on the CIVλλ5801/12 emission-line variability observed for NGC 1501 and NGC 6751 (see also Acker & Durand, these proceedings). Main results: NGC 1501: The OVλ5590 and CIVλλ5801/12 emission lines as well as the CIV/CIII complex around 5690Å are variable at the 1% level. The amplitudes of the variations range from about 5% (OV), up to 7% (CIV) of the adjacent continuum flux. The HeIλ5876 is also found to be variable; NGC 6751: For this star, significant variability at the 1% level is detected for the CIVλλ5801/12 emission line only. Note that the variations are quite huge since they span 6–10% of the adjacent continuum flux. Small variations are seen around the line centre but they are essentially located in the red and blue wings of the line, the latter showing the largest level of variability. Generally, the amplitudes of the variations in [WO 4] central stars range up to 10% of the adjacent continuum flux, over timescales of hours, or days. This result is essentially the same than that found for [WC]-late type stars. We expect strong, hydrogen-deficient [WC] winds to be extreme examples for central stars of PN, so that any fine structure found in [WC] winds may apply to all winds of central stars of PN, much as one is finding now that weak, massive O-star winds also show the same fine structure as massive WR winds. The consequences of clumping in hot-star winds are manifold, including substantial constraints on the effective mass-loss rates, and their possible impact on the surrounding nebula itself (Acker et al. 2002). On the whole, the winds of all [WC] central stars are significantly stochastically variable on relatively short time-scales. This supports a turbulent origin.
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Owocki, Stanley P., and Kenneth G. Gayley. "The dynamics of Wolf-Rayet winds." Symposium - International Astronomical Union 163 (1995): 138–46. http://dx.doi.org/10.1017/s0074180900201794.
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We review the dynamics of Wolf-Rayet stellar winds, with emphasis on how multi-line scattering can lead to mass loss rates for which the wind's radial momentum flux Ṁv∞ greatly exceeds the limit for single-scattering of the star's radiative momentum L*/c. The geometrical considerations that allow this to occur are illuminated through connections to multiple scattering in an effectively gray medium. The so-called “WR wind momentum problem” would be better characterized as an “opacity problem” of simply identifying a sufficiently dense ensemble of optically thick lines.
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Wu, Jin. "Wind-Stress Coefficients at Light Winds." Journal of Atmospheric and Oceanic Technology 5, no. 6 (December 1988): 885–88. http://dx.doi.org/10.1175/1520-0426(1988)005<0885:wscalw>2.0.co;2.
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Toba, Yoshiaki, Kozo Okada, and Ian S. F. Jones. "The Response of Wind-Wave Spectra to Changing Winds. Part I: Increasing Winds." Journal of Physical Oceanography 18, no. 9 (September 1988): 1231–40. http://dx.doi.org/10.1175/1520-0485(1988)018<1231:trowws>2.0.co;2.
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Wright, Ethan E., Mark A. Bourassa, Ad Stoffelen, and Jean-Raymond Bidlot. "Characterizing Buoy Wind Speed Error in High Winds and Varying Sea State with ASCAT and ERA5." Remote Sensing 13, no. 22 (November 12, 2021): 4558. http://dx.doi.org/10.3390/rs13224558.
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Buoys provide key observations of wind speed over the ocean and are routinely used as a source of validation data for satellite wind products. However, the movement of buoys in high seas and the airflow over waves might cause inaccurate readings, raising concern when buoys are used as a source of wind speed comparison data. The relative accuracy of buoy winds is quantified through a triple collocation (TC) exercise comparing buoy winds to winds from ASCAT and ERA5. Differences between calibrated buoy winds and ASCAT are analyzed through separating the residuals by anemometer height and testing under high wind-wave and swell conditions. First, we converted buoy winds measured near 3, 4, and 5 m to stress-equivalent winds at 10 m (U10S). Buoy U10S from anemometers near 3 m compared notably lower than buoy U10S from anemometers near 4 and 5 m, illustrating the importance of buoy choice in comparisons with remote sensing data. Using TC calibration of buoy U10S to ASCAT in pure wind-wave conditions, we found that there was a small, but statistically significant difference between height adjusted buoy winds from buoys with 4 and 5 m anemometers compared to the same ASCAT wind speed ranges in high seas. However, this result does not follow conventional arguments for wave sheltering of buoy winds, whereby the lower anemometer height winds are distorted more than the higher anemometer height winds in high winds and high seas. We concluded that wave sheltering is not significantly affecting the winds from buoys between 4 and 5 m with high confidence for winds under 18 ms−1. Further differences between buoy U10S and ASCAT winds are observed in high swell conditions, motivating the need to consider the possible effects of sea state on ASCAT winds.
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Hoai, Do Thi, Pham Tuyet Nhung, Pham Tuan-Anh, Pierre Darriulat, Pham Ngoc Diep, Nguyen Thi Phuong, and Tran Thi Thai. "On the origin of high Doppler velocity wings in the spectra of O-rich AGB stars." EPJ Web of Conferences 240 (2020): 05001. http://dx.doi.org/10.1051/epjconf/202024005001.
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Millimetre ALMA observations of the nascent winds of several Oxygen rich AGB stars have revealed the high Doppler velocity wings in their spectra. However, the physics underlying their production is unclear. In this paper, we illustrate the argument with four examples of oxygen-rich AGB stars: EP Aqr, R Dor, L2 Pup and Mira Ceti.
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Güdel, Manuel. "Observational constraints for solar-type Stellar winds." Proceedings of the International Astronomical Union 15, S354 (June 2019): 313–32. http://dx.doi.org/10.1017/s1743921320001441.
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AbstractIonized winds from late-type main-sequence stars are important for stellar spin-down and therefore the evolution of stellar activity; winds blow an “astrosphere” into the interstellar medium that absorbs a large part of galactic cosmic rays; and the winds play a key role in shaping planetary environments, in particular their upper atmospheres. These issues have been well studied for the solar wind but little is known about winds escaping from other solar-type stars. Several methods have been devised to either detect winds directly or to infer the presence of such winds from features that are shaped by the winds. This paper summarizes these methods and discusses exemplary findings. There is need for more studies using multiple methods for the same stars.
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Gibbons, R. "Winds." Literary Imagination 2, no. 3 (January 1, 2000): 375–76. http://dx.doi.org/10.1093/litimag/2.3.375.
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Holaday, Nathan. "Winds." Appalachian Heritage 16, no. 1 (1988): 15. http://dx.doi.org/10.1353/aph.1988.0011.
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MacGregor, K. B. "Winds." International Astronomical Union Colloquium 137 (1993): 620–33. http://dx.doi.org/10.1017/s0252921100018534.
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AbstractIt is by now well known that most main sequence stars continuously lose mass as a consequence of the winds they emit. In addition to affecting the thermal and dynamical state of the stellar atmosphere, such mass loss can also induce changes in the interiors of stars. In the present review, we consider a few of the ways in which sustained, wind-like mass loss can alter the physical state of main sequence stellar interiors by examining the differences in internal structure, composition, and rotation between mass-losing and conservatively evolving stars.
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Greet, P. A., J. L. Innis, and P. L. Dyson. "Thermospheric vertical winds in the auroral oval/polar cap region." Annales Geophysicae 20, no. 12 (December 31, 2002): 1987–2001. http://dx.doi.org/10.5194/angeo-20-1987-2002.
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Abstract. Thermospheric mean vertical winds from high-resolution Fabry-Perot Spectrometer observations of the l630 nm emission (from ~ 240 km altitude), over a four year interval 1997–2000, from Mawson (67.6° S, 62.9° E, Inv 70.5° S) and Davis (68.6° S, 78.0° E, Inv 74.6° S) are presented. Combining the four years of data shows Mawson mean hourly vertical winds vary between -10 ms-1 and +4 ms-1, while Davis mean hourly vertical winds vary between - 0 ms-1 and +10 ms-1. Mean hourly vertical winds from Mawson show little change with Kp, while at Davis the range of variation increases with increasing geomagnetic activity. Histograms of frequency distributions of such winds, and their variations with Kp and l630 nm emission intensity, are presented and discussed. Variations in mean hourly thermospheric winds and l630 nm emission intensities show at least three significant associations between mean vertical winds and the auroral oval. Mean vertical winds within the auroral oval are smaller than those outside the oval, particularly those in the polar cap. A downward wind associated with entry of the observing region into the auroral oval can be seen in both Mawson and Davis hourly mean vertical winds. Large vertical winds are seen poleward of the auroral oval/polar cap boundary, most significantly upward winds occur within ± 2 hr of magnetic midnight. Under moderately quiet geomagnetic conditions Davis passes through the auroral oval into the polar cap in the evening, but at higher Kp it passes into the polar cap earlier and larger, and more sustained mean vertical winds are observed.Key words. Meteorology and atmospheric dynamics (thermospheric dynamics)
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Murray, William M. "Do modern winds equal ancient winds?" Mediterranean Historical Review 2, no. 2 (December 1987): 139–67. http://dx.doi.org/10.1080/09518968708569525.
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Sandford, D. J., C. L. Beldon, R. E. Hibbins, and N. J. Mitchell. "Dynamics of the Antarctic and Arctic mesosphere and lower thermosphere – Part 1: Mean winds." Atmospheric Chemistry and Physics Discussions 10, no. 7 (July 20, 2010): 17527–67. http://dx.doi.org/10.5194/acpd-10-17527-2010.
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Abstract. Zonal and meridional winds have been measured in the upper mesosphere and lower thermosphere at polar latitudes using two ground-based meteor radars. One radar is located at Rothera (68° S, 68° W) in the Antarctic and has been operational since February 2005. The second radar is located at Esrange (68° N, 21° E) in the Arctic and has been operational since October 1999. Both radars have produced relatively continuous measurements. Here we consider measurements made up to the end of 2009. Both radars are of similar design and at conjugate geographical latitudes, making the results directly comparable and thus allowing investigation of the differences in the mean winds of the Antarctic and Arctic regions. The data from each radar have been used to construct climatologies of monthly-mean zonal and meridional winds at heights between 80 and 100 km. Both Antarctic and Arctic data sets reveal seasonally varying zonal and meridional winds in which the broad pattern repeats from year to year. In particular, the zonal winds display a strong shear in summer associated with the upper part of the westward summertime zonal jet. The winds generally reverse to eastward flow at heights of ~90 km. The zonal winds are eastward throughout the rest of the year. The meridional winds are generally equatorward throughout the year over both sites, although brief episodes of poleward flow are often evident near the equinoxes. The strongest equatorward flows occur at heights of ~90 km during summer. There are significant differences between the mean winds observed in the Antarctic and Arctic. In particular, the westward winds in summer are stronger and occur earlier in the season in the Antarctic compared with the Arctic. The eastward winds evident above the summertime zonal wind reversal are significantly stronger in the Arctic. The summertime equatorward flow in the Antarctic is slightly weaker, but occurs over a greater depth than is the case in the Arctic. Comparisons of these observations with those of the URAP and HWM-07 empirical models reveal a number of significant differences. In particular, the zonal winds observed in the Antarctic during wintertime are significantly weaker than those of URAP. However, the URAP zonal winds are a good match to the observations of the Arctic. Significant differences are evident between the observations and HWM-07. In particular, the strong wintertime zonal winds of the Arctic in HWM-07 are not evident in the observations and the summertime zonal winds in HWM-07 are systematically stronger than observed. The agreement with meridional winds is generally poor. There is a significant amount of inter-annual variability in the observed zonal and meridional winds. Particularly high variability is observed in the Arctic zonal winds in spring and is probably associated the stratospheric warmings.
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Sandford, D. J., C. L. Beldon, R. E. Hibbins, and N. J. Mitchell. "Dynamics of the Antarctic and Arctic mesosphere and lower thermosphere – Part 1: Mean winds." Atmospheric Chemistry and Physics 10, no. 21 (November 4, 2010): 10273–89. http://dx.doi.org/10.5194/acp-10-10273-2010.
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Abstract. Zonal and meridional winds have been measured in the upper mesosphere and lower thermosphere at polar latitudes using two ground-based meteor radars. One radar is located at Rothera (68° S, 68° W) in the Antarctic and has been operational since February 2005. The second radar is located at Esrange (68° N, 21° E) in the Arctic and has been operational since October 1999. Both radars have produced relatively continuous measurements. Here we consider measurements made up to the end of 2009. Both radars are of similar design and at conjugate geographical latitudes, making the results directly comparable and thus allowing investigation of the differences in the mean winds of the Antarctic and Arctic regions. The data from each radar have been used to construct climatologies of monthly-mean zonal and meridional winds at heights between 80 and 100 km. Both Antarctic and Arctic data sets reveal seasonally varying zonal and meridional winds in which the broad pattern repeats from year to year. In particular, the zonal winds display a strong shear in summer associated with the upper part of the westward summertime zonal jet. The winds generally reverse to eastward flow at heights of ~90 km. The zonal winds are eastward throughout the rest of the year. The meridional winds are generally equatorward over both sites, although brief episodes of poleward flow are often evident near the equinoxes and during winter. The strongest equatorward flows occur at heights of ~90 km during summer. There are significant differences between the mean winds observed in the Antarctic and Arctic. In particular, the westward winds in summer are stronger and occur earlier in the season in the Antarctic compared with the Arctic. The eastward winds evident above the summertime zonal wind reversal are significantly stronger in the Arctic. The summertime equatorward flow in the Antarctic is slightly weaker, but occurs over a greater depth than is the case in the Arctic. Comparisons of these observations with those of the URAP and HWM-07 empirical models reveal a number of significant differences. In particular, the zonal winds observed in the Antarctic during wintertime are significantly weaker than those of URAP. However, the URAP zonal winds are a good match to the observations of the Arctic. Significant differences are evident between the observations and HWM-07. In particular, the strong wintertime zonal winds of the Arctic in HWM-07 are not evident in the observations and the summertime zonal winds in HWM-07 are systematically stronger than observed. The agreement with meridional winds is generally poor. There is a significant amount of inter-annual variability in the observed zonal and meridional winds. Particularly high variability is observed in the Arctic zonal winds in spring and is probably associated with stratospheric warmings.
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Perrie, Will, Weiqing Zhang, Mark Bourassa, Hui Shen, and Paris W. Vachon. "Impact of Satellite Winds on Marine Wind Simulations." Weather and Forecasting 23, no. 2 (April 1, 2008): 290–303. http://dx.doi.org/10.1175/2007waf2006093.1.
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Abstract A variational data assimilation method is applied to remotely sensed wind data from Hurricanes Gustav (2002) and Isabel (2003) to produce enhanced marine wind estimates. The variational method utilizes constraints to ensure that an optimum combination of winds is determined, in the sense of minimization of a cost function measuring the misfit between observations and background input field data and constraining nongeophysical features in the spatial derivatives. Constraints are multiplied by weights, which are objectively determined by cross validation. Verification is obtained by comparison with available operational in situ buoy observations and analyses winds. It is shown that the newly constructed midlatitude wind fields represent an improvement relative to background wind field estimates and also relative to Quick Scatterometer–National Centers for Environmental Prediction reanalysis blended winds, and that the new winds have an impact on simulations of waves and upper-ocean currents.
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HASHIGUCHI, Hiroyuki. "Remote Sensing Techniques of Winds: Wind Profiler." Wind Engineers, JAWE 34, no. 3 (2009): 333–36. http://dx.doi.org/10.5359/jawe.34.333.
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Harris, A. "The winds of change [offshore wind energy]." Engineering & Technology 5, no. 2 (February 6, 2010): 40–43. http://dx.doi.org/10.1049/et.2010.0208.
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Lépine, Sébastien. "Effects of wind clumping on colliding winds." Symposium - International Astronomical Union 163 (1995): 411–15. http://dx.doi.org/10.1017/s0074180900202386.
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Recent studies of variable Wolf-Rayet emission lines reveal a hierarchy of structures, characterized by power laws analogous to what is expected from supersonic compressible turbulence. The collision of inhomogeneous winds can be very different from the case of smooth winds. The difference will mainly depend on two factors: (i) the relative importance of the inhomogeneous compared to the homogeneous component; and (ii) the characteristic filling factor of the inhomogeneous component. Using relations derived from observations of variable line structures (“blobs”), it can be deduced that the flux emitted by the inhomogeneous part of the wind of a WR star is dominated by its smallest structures. This implies that a significant fraction of the underlying emission line profile could be produced by small, undetectable inhomogeneities. It can also be deduced that the volume spanned by the inhomogeneities is dominated by the largest structures. This in turn implies that the filling factor should be low, or that we are dealing with a fractal-like hierarchy. It is suggested that the wind is composed of dense structures separated by large “voids” which may actually be filled by a homogeneous wind component. The interacting zone of two inhomogeneous colliding winds should thus be much more extended in space than for a smooth-wind model, because the dense, inhomogeneous structures are able to penetrate through the large “voids”.
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Lander, Mark, James C. Sadler, Jose Maliekal, and Arnold Hori. "Tropical Wind Stress from Time-Averaged Winds." Journal of Applied Meteorology 28, no. 9 (September 1989): 904–12. http://dx.doi.org/10.1175/1520-0450(1989)028<0904:twsfta>2.0.co;2.
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Gaffin, David M. "On High Winds and Foehn Warming Associated with Mountain-Wave Events in the Western Foothills of the Southern Appalachian Mountains." Weather and Forecasting 24, no. 1 (February 1, 2009): 53–75. http://dx.doi.org/10.1175/2008waf2007096.1.
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Abstract Extremely high winds of 40–49 m s−1 [90–110 miles per hour (mph)] were reported across the western foothills of the southern Appalachian Mountains on 22–23 December 2004, 17 October 2006, 24–25 February 2007, and 1 March 2007. The high winds in all four of these events were determined to be the result of mountain waves, as strong southeast winds became perpendicular to the mountains with a stable boundary layer present below 750 hPa and a veering wind profile that increased with height. Adiabatic warming of the descending southeasterly winds was also observed at the Knoxville airport during all four events (although of varying intensities), with the 850-hPa air mass immediately upwind of the Smoky Mountains determined to be the source region of these foehn winds. An interesting similarity among these four events was the location of the strongest 850-hPa winds northwest of the region, with a rapidly decreasing speed gradient observed over the mountains. These 850-hPa winds northwest of the mountains were also stronger than the 700-hPa winds in the region. It was hypothesized that strong low-level divergence developed in the foothills, as the stronger 850-hPa winds on the western side accelerated away from the mountains while the mountains prevented a rapid return flow from the eastern side. This low-level divergence likely helped to further strengthen the mountain-wave-induced mesolow and high winds in the western foothills. A 12-yr climatology of high wind events induced by mountain waves at Cove Mountain was also constructed. This climatology revealed that these events occurred primarily at night between November and March. Composite maps of mountain-wave events that produced warning-level and advisory-level winds revealed that an axis of stronger 850-hPa winds was typically located west of the mountains (away from the foothills). This finding (using reanalysis data instead of model data) further suggested that low-level divergence normally contributed to the intensity of mountain-wave-induced mesolows and winds in the western foothills of the southern Appalachian Mountains.
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Bhattacharya, Y., and A. J. Gerrard. "Correlations of mesospheric winds with subtle motion of the Arctic polar vortex." Atmospheric Chemistry and Physics Discussions 9, no. 4 (August 6, 2009): 16549–62. http://dx.doi.org/10.5194/acpd-9-16549-2009.
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Abstract. This paper investigates the relationship between high latitude upper mesospheric winds and the state of the stratospheric polar vortex in the absence of major sudden stratospheric warmings. A ground based Michelson Interferometer stationed at Resolute Bay (74°43´ N, 94°58´ W) in the Canadian High Arctic is used to measure mesopause region neutral winds using the hydroxyl (OH) Meinel-band airglow emission (central altitude of ~85 km). These observed winds are compared to analysis winds in the upper stratosphere during November and December of 1995 and 1996; years characterized as cold, stable polar vortex periods. Correlation of mesopause wind speeds with those from the upper stratosphere is found to be significant for the 1996 season when the polar vortex is subtly displaced off its initial location by a strong Aleutian High. These mesopause winds are observed to lead stratospheric winds by approximately two days with increasing (decreasing) mesospheric winds predictive of decreasing (increasing) stratospheric winds. No statistically significant correlations are found for the 1995 season when there is no such displacement of the polar vortex.
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Bhattacharya, Y., and A. J. Gerrard. "Correlations of mesospheric winds with subtle motion of the Arctic polar vortex." Atmospheric Chemistry and Physics 10, no. 2 (January 19, 2010): 431–36. http://dx.doi.org/10.5194/acp-10-431-2010.
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Abstract. This paper investigates the relationship between high latitude upper mesospheric winds and the state of the stratospheric polar vortex in the absence of major sudden stratospheric warmings. A ground based Michelson Interferometer stationed at Resolute Bay (74°43' N, 94°58' W) in the Canadian High Arctic is used to measure mesopause region neutral winds using the hydroxyl (OH) Meinel-band airglow emission (central altitude of ~85 km). These observed winds are compared to analysis winds in the upper stratosphere during November and December of 1995 and 1996; years characterized as cold, stable polar vortex periods. Correlation of mesopause wind speeds with those from the upper stratosphere is found to be significant for the 1996 season when the polar vortex is subtly displaced off its initial location by a strong Aleutian High. These mesopause winds are observed to lead stratospheric winds by approximately two days with increasing (decreasing) mesospheric winds predictive of decreasing (increasing) stratospheric winds. No statistically significant correlations are found for the 1995 season when there is no such displacement of the polar vortex.
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Kirkwood, Sheila, Evgenia Belova, Peter Voelger, Sourav Chatterjee, and Karathazhiyath Satheesan. "Extended validation of Aeolus winds with wind-profiling radars in Antarctica and Arctic Sweden." Atmospheric Measurement Techniques 16, no. 18 (September 20, 2023): 4215–27. http://dx.doi.org/10.5194/amt-16-4215-2023.
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Abstract. Winds from two wind-profiling radars, ESRAD (ESrange atmospheric RADar) in Arctic Sweden and MARA (Moveable Atmospheric Radar for Antarctica) on the coast of Antarctica, are compared with collocated (within 100 km) winds measured by the Doppler lidar on board the Aeolus satellite for the time period July 2019–May 2021 (baseline 2B11). Data are considered as a whole and subdivided into summer and winter as well as ascending (afternoon) and descending (morning) passes. Mean differences (bias) and random differences are categorized (standard deviation and scaled median absolute deviation) and the effects of different quality criteria applied to the data are assessed, including the introduction of the “modified Z score” to eliminate gross errors. This last criterion has a substantial effect on the standard deviation, particularly for Mie winds. Significant bias is found in two cases, for Rayleigh winds for the descending satellite passes. at MARA (−1.4 (+0.7) m s−1) and for all Mie winds at ESRAD (+1.0 (+0.3) m s−1). For the Rayleigh winds at MARA, there is no obvious explanation for the bias in the data distribution. The Mie wind error with respect to the wind data measured at ESRAD shows a skewed distribution toward positive values (Aeolus horizontal line-of-sight wind > ESRAD wind). Random differences (scaled median absolute deviation) for all data together are 5.9 and 5.3 m s−1 for Rayleigh winds at MARA and ESRAD, respectively, and 4.9 and 3.9 m s−1 for Mie winds. When the comparison is restricted to Aeolus measurements with a mean location within 25 km from the radars, there is no change to the random differences for Rayleigh winds, but for Mie winds they are reduced to 3.3 and 3.6 m s−1. These represent an upper bound for Aeolus wind random errors since they are due to a combination of spatial differences and random errors in both radar winds and Aeolus winds. The random errors in radar winds are < 2 m s−1 and therefore contribute little, but spatial variability clearly makes a significant contribution for Mie winds, especially at MARA.
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Giyasov, A. "THE SIGNIFICANCE OF AN URBAN HEAT ISLAND IN THE REGULATION OF MICRO- AND ECO-CLIMATES." Bulletin of South Ural State University series "Construction Engineering and Architecture" 23, no. 1 (2023): 5–15. http://dx.doi.org/10.14529/build230101.
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This article determines the most significant features of the urban climate – heat islands – which are characterized by higher air temperatures and thermal regime of the active surface compared to the countryside. Differences in temperature and thermal conditions are noticeably manifested in cities of southern geographic latitudes. The study identifies the role of the urban heat island in the regulation of micro- and eco-climates and provides a classification of urban winds. A mathematical model of the urban heat island and its transformation has been compiled. Possible methods for the formation of architectural planning, and the volumetric and compositional organization of the urban landscape, which contribute to the wind’s natural ventilation of urban areas at the meso- and micro-climate levels, are determined. The importance of the urban heat island in the formation of micro- and eco-climates has been established. A model of air circulation has been created: macro-aeration – local air circulation occurring in a large geographical landscape, between the city and the suburbs, water areas and forests; meso-aeration – local winds that develop within a densely built-up area, alternating urban areas and green areas; micro-aeration – local winds in the interval of green and non-green zones, in the space between insolated and shaded facades; nano-aeration – local winds between small patches of warm and cold islands in an urban area. The study give suggestions for further research on identifying transformational changes on the heat islands of cities at the macro-, meso-, micro- and nano-scale and possible methods for including them in architectural and construction planning and construction of buildings and structures.
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Kam, Hosik, Young-Sil Kwak, Tae-Yong Yang, Yong Ha Kim, Jeongheon Kim, Jaewook Lee, Seonghwan Choi, and Ji-Hye Baek. "Characteristics of Horizontal Winds in the Mesosphere and Lower Thermosphere Region over Korean Peninsula Observed from the Korea Astronomy and Space Science Institute Meteor Radar." Journal of Astronomy and Space Sciences 38, no. 4 (December 2021): 229–36. http://dx.doi.org/10.5140/jass.2021.38.4.229.
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We present for the first time the characteristics of upper atmospheric horizontal winds over the Korean Peninsula. Winds and their variability are derived using four-year measurements by the Korea Astronomy and Space Science Institute (KASI) meteor radar. A general characteristic of zonal and meridional winds is that they exhibit distinct diurnal and seasonal variations. Their changes indicate sometimes similar or sometimes different periodicities. Both winds are characterized by either semi-diurnal tides (12 hour period) and/or diurnal tides (24 hour period) from 80–100 km. In terms of annual change, the annual variation is the strongest component in both winds, but semi-annual and ter-annual variations are only detected in zonal winds.
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Gayley, K. G. "Inhibition of Wind-Compressed Disk Inhibition in Optically Thick Winds." Symposium - International Astronomical Union 215 (2004): 527–28. http://dx.doi.org/10.1017/s0074180900196147.
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There are three important effects in optically thin line-driven winds that have been shown to inhibit the equatorial compression inherent in the wind-compressed disk model:1) gravity darkening, which concentrates the driving flux over the poles,2) stellar oblateness, which rotates the flux vectors poleward, and3) nonisotropic opacity, which rotates the force vectors poleward.The first two of these effects tend to yield fairly spherical winds, while the last one actually reverses the wind compression and should generate prolate winds. This poster argues that this third mechanism is not present for multiline scattering in Wolf-Rayet winds. Hence, it is argued that rotating optically thick line-driven winds should have a more spherical UV photosphere, especially for CAK α ≅ 2/3. However, owing to flux migration from polar to equatorial regions, such winds should have an even more prolate optical photosphere.
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Venkateswara Rao, N., T. Tsuda, and Y. Kawatani. "A remarkable correlation between short period gravity waves and semiannual oscillation of the zonal wind in the equatorial mesopause region." Annales Geophysicae 30, no. 4 (April 19, 2012): 703–10. http://dx.doi.org/10.5194/angeo-30-703-2012.
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Abstract. The variability of zonal winds and the horizontal wind velocity variance of short period (20–120 min) gravity waves (GWs) in the equatorial mesopause region are studied using medium frequency (MF) radar observations from Pameungpeuk (7.4° S, 107.4° E) during 2004–2010. The zonal winds display a distinct semiannual oscillation (called mesospheric semiannual oscillation, MSAO), with westward winds during equinoxes and eastward winds during solstices. Furthermore, the westward winds during March equinox are larger during 2008 and 2009. The short period GW variance also shows a semiannual oscillation with enhanced activity during equinoxes. A good correlation is observed between the zonal winds and the short period GW variance from 2008–2010, with the winds being westward during the times of enhanced GW activity. Such a correlation, however, is less obvious during 2004–2006. The long period (10–20 h) GW variance, on the other hand, does not show such a correlation throughout the observation period.
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Pascual, Daniel, Maria Paola Clarizia, and Christopher S. Ruf. "Improved CYGNSS Wind Speed Retrieval Using Significant Wave Height Correction." Remote Sensing 13, no. 21 (October 27, 2021): 4313. http://dx.doi.org/10.3390/rs13214313.
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This article presents the methodology for an improved estimation of the sea surface wind speed measured by the cyclone global navigation satellite system (CYGNSS) constellation of satellites using significant wave height (SWH) information as external reference data. The methodology consists of a correcting 2D look-up table (LUT) with inputs: (1) the CYGNSS wind speed given by the geophysical model function (GMF); and (2) the collocated reference SWH given by the WW3 model, which is forced by winds from the European Centre for Medium-Range Weather Forecasts (ECMWF) organization. In particular, the analyzed CYGNSS wind speeds are the fully developed seas (FDS) obtained with the GMF 3.0, and the forcing winds are the ECMWF forecast winds. Results show an increase in sensitivity to large winds speeds and an overall reduction in the root mean square difference (RMSD) with respect to the ECMWF winds from 2.05 m/s to 1.74 m/s. The possible influence of the ECWMF winds on the corrected winds (due to their use in the WW3 model) is analyzed by considering the correlation between: (1) the difference between the ECMWF winds and those from another reference; and (2) the difference between the corrected CYGNSS winds and those from the same reference. Results using ASCAT, WindSat, Jason, and AltiKa as references show no significant influence.
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Salim, M., K. Nagendra, S. Bansal, R. K. Nayak, M. S. Rao, S. K. Sasmal, C. B. S. Dutt, K. H. Rao, and V. K. Dadhwal. "Assessment of OSCAT winds for coastal circulation on the north western continental shelf of India." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-8 (November 28, 2014): 1073–77. http://dx.doi.org/10.5194/isprsarchives-xl-8-1073-2014.
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Winds and tides are the major driving forces of the circulation in the coastal and marginal seas. Data Interpolating Variation Analysis (DIVA) method is used to generate spatial and time series data of sea surface winds for the period 2010–2013 at daily time scale from the OSCAT observations. Validity and consistency of the data were examined against the in situ observations and ECMWF re-analysis at different time scales. Amplitude of semi-annual cycle of OSCAT winds in the coastal domain is 30 % larger than the ECMWF winds while the amplitude of annual cycle of OSCAT winds is 20 % smaller than the ECMWF winds. On the open oceans, intensity of respective semi-annual cycles are mostly similar while annual cycle of OSCAT wind is 20 % smaller than the ECMWF winds. Wind driven currents over the western continental shelf of India were simulated by forcing OSCAT and ECMWF winds to a coastal circulation model. It is observed that the mean seasonal circulations from both the simulations are identical spatial pattern however the magnitude of simulated currents based on OSCAT winds are much stronger than ECMWF wind forcing. These currents used in a lagrangian tracer transport code to model the oil-spill events occurred in this region. It revealed that OSCAT based ocean currents has performed better in simulating the trajectory than the ECMWF wind driven currents.
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Deb, S. K., C. M. Kishtawal, and P. K. Pal. "Impact of Kalpana-1-Derived Water Vapor Winds on Indian Ocean Tropical Cyclone Forecasts." Monthly Weather Review 138, no. 3 (March 1, 2010): 987–1003. http://dx.doi.org/10.1175/2009mwr3041.1.
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Abstract The water vapor winds from the operational geostationary Indian National Satellite (INSAT) Kalpana-1 have recently become operational at the Space Applications Centre (SAC). A series of experimental forecasts are attempted here to evaluate the impact of water vapor winds derived from Kalpana-1 for the track and intensity prediction of two Bay of Bengal tropical cyclones (TCs), Sidr and Nargis, using the Weather Research and Forecasting (WRF) modeling system. The assimilation of water vapor winds has made some impact in the initial position errors as well as track forecasts when compared with the corresponding control experiments for both TCs. However, no statistically significant improvement is noticed in the simulations of TC intensities [i.e., minimum sea level pressure (MSLP) and maximum surface winds forecasts when satellite winds are used for assimilation]. Moreover, the performance of Kalpana-1 winds is evaluated by repeating the same sets of experiments using Meteosat-7 winds derived at the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) and compared with observed data. The simulation of initial position errors, and track and intensity forecasts using the assimilation of water vapor winds from both satellites are comparable. Though, these results are preliminary with respect to the Kalpana-1 winds, the present study can provide some insight to the WRF model users over the Indian Ocean region.
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Carvalho, Leila, Gert-Jan Duine, Charles Jones, Katelyn Zigner, Craig Clements, Heather Kane, Chloe Gore, et al. "The Sundowner Winds Experiment (SWEX) Pilot Study: Understanding Downslope Windstorms in the Santa Ynez Mountains, Santa Barbara, California." Monthly Weather Review 148, no. 4 (March 18, 2020): 1519–39. http://dx.doi.org/10.1175/mwr-d-19-0207.1.
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Abstract Sundowner winds are downslope gusty winds often observed on the southern slopes of the Santa Ynez Mountains (SYM) in coastal Santa Barbara (SB), California. They typically peak near sunset and exhibit characteristics of downslope windstorms through the evening. They are SB’s most critical fire weather in all seasons and represent a major hazard for aviation. The Sundowner Winds Experiment Pilot Study was designed to evaluate vertical profiles of winds, temperature, humidity, and stability leeward of the SYM during a Sundowner event. This was accomplished by launching 3-hourly radiosondes during a significant Sundowner event on 28–29 April 2018. This study showed that winds in the lee of the SYM exhibit complex spatial and temporal patterns. Vertical profiles showed a transition from humid onshore winds from morning to midafternoon to very pronounced offshore winds during the evening after sunset. These winds accompanied mountain waves and a northerly nocturnal lee jet with variable temporal behavior. Around sunset, the jet was characterized by strong wind speeds enhanced by mountain-wave breaking. Winds weakened considerably at 2300 PDT 29 April but enhanced dramatically at 0200 PDT 29 April at much lower elevations. These transitions were accompanied by changes in stability profiles and in the Richardson number. A simulation with the Weather Research and Forecasting (WRF) Model at 1-km grid spacing was examined to evaluate the skill of the model in capturing the observed winds and stability profiles and to assess mesoscale processes associated with this event. These results advanced understanding on Sundowner’s spatiotemporal characteristics and driving mechanisms.
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Shimada, Teruhisa. "Structures and Seasonal Variations of Surface Winds Blowing through the Tsushima Strait." Journal of Applied Meteorology and Climatology 49, no. 8 (August 1, 2010): 1714–27. http://dx.doi.org/10.1175/2010jamc2301.1.
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Abstract Surface winds blowing through the Tsushima Strait are statistically investigated using satellite wind measurements and atmospheric reanalysis data. This study first presents structures and seasonal variations of the northeasterly and southwesterly along-strait winds by imposing newly proposed conditions for defining them. Although the speeds of the northeasterly along-strait winds are generally high within the entire strait, the maximum wind speeds are located downwind of the two channels. The southwesterly along-strait winds start to accelerate at the west exit within the strait. Weak-wind regions are formed in the lee of Tsushima Island in both cases. The occurrence frequencies of the northeasterly and southwesterly along-strait winds are high (low) in the warm (cool) season. The northeasterly along-strait winds are more often observed than the southwesterly along-strait winds. The frequency of the northeasterly along-strait wind is extraordinarily high in September, but the averaged wind speed is comparable to those in the other months. Most of the southwesterly along-strait wind cases fall within low-Froude-number regimes, suggesting the significant effects of Tsushima Island on the wind in the strait. Synoptic situations favorable for the along-strait winds are investigated. Correlations between the along-strait wind component and sea level pressure (SLP) indicate that the along-strait winds are induced by SLP perturbations primarily over the Japan Sea and secondarily on the south of the strait. In addition, cluster analysis of the SLP fields shows four representative SLP fields favorable for the along-strait winds and their monthly occurrence frequencies.
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Hibbins, R. E., and M. J. Jarvis. "A long-term comparison of wind and tide measurements in the upper mesosphere recorded with an imaging Doppler interferometer and SuperDARN radar at Halley, Antarctica." Atmospheric Chemistry and Physics Discussions 7, no. 3 (May 16, 2007): 6573–601. http://dx.doi.org/10.5194/acpd-7-6573-2007.
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Abstract. Data from a co-located imaging Doppler interferometer and SuperDARN radar recorded since 1996 have been analysed in a consistent manner to determine daily mean winds and tides in the upper mesosphere. By comparing only days when both techniques were recording good quality data it is shown that the SuperDARN radar winds and tides correlate best with the IDI height bin 90–95 km. On timescales of one hour the winds derived from each technique correlate poorly, whereas the daily mean winds are in much better agreement suggesting that the two radars are sensitive to different parts of the gravity wave spectrum. Regression analysis reveals that the observed SuperDARN daily mean meridional wind strength is approximately 65% that recorded by the IDI while the zonal winds are of similar magnitude, in good quantitative agreement with previous studies which have shown contamination to SuperDARN-derived winds due to the significant back lobe of the radar radiation pattern. Climatologically the two techniques observe similar monthly mean winds with the SuperDARN meridional winds suppressed compared to the IDI which tends to record winds more poleward and eastward than those derived by the SuperDARN radar during the summer months, and to be slightly more equatorward during the winter. The 12-h tidal amplitude and phase in both the zonal and meridional components derived from both techniques are in excellent agreement, whereas the 24-h tides are seen much more strongly in the SuperDARN radar, especially in wintertime, with poor phase agreement. Long term comparison of the two techniques reveals a tendency for the IDI meridional winds to be more poleward during solar maximum especially during summer time; an effect which is not reproduced in the meridional winds derived from the SuperDARN radar. These results are discussed in the context of previous studies to independently determine the veracity of each technique.
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Samelson, R. M., and P. L. Barbour. "Low-Level Jets, Orographic Effects, and Extreme Events in Nares Strait: A Model-Based Mesoscale Climatology." Monthly Weather Review 136, no. 12 (December 1, 2008): 4746–59. http://dx.doi.org/10.1175/2007mwr2326.1.
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Abstract A mesoscale atmospheric model, nested in operational global numerical weather prediction fields, is used to estimate low-level winds and surface wind stress through Nares Strait, between Ellesmere Island and Greenland, during 2 yr from August 2003 to July 2005. During most of the year, the model low-level winds are dominated by intense, southward along-strait flow, with monthly-mean southward 10-m winds reaching 10 m s−1 in winter. Summertime flow is weak and distributions of hourly along-strait winds during the 2-yr period are strongly bimodal. The strong southward low-level winds are associated with ageostrophic, orographically channeled flow down the pressure gradient from the Lincoln Sea to Baffin Bay and are highly correlated with the pressure difference along Nares Strait. The 2-yr means and leading EOFs of monthly-mean 10-m winds and wind stress place the strongest winds and stress in the southern parts of Smith Sound and of Kennedy Channel, at the openings to Baffin Bay and Kane Basin, at known sites of polynya formation, including the North Water polynya in Smith Sound, suggesting that the locally intensified winds may cause these persistent polynyas. An intense wind event observed in Nares Strait by a field camp, with surface winds exceeding 30 m s−1, generally follows the typical pattern of these low-level flows. Based on the model correlation of winds and pressure difference, a 51-yr time series of estimated winds in Nares Strait is reconstructed from historical surface pressure measurements at Thule, Greenland, and Alert, Canada. The pressure difference and reconstructed wind time series are correlated with the Arctic Oscillation at annual and longer periods, but not on monthly periods.
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Rodenkirch, P. J., and C. P. Dullemond. "Dust entrainment in magnetically and thermally driven disk winds." Astronomy & Astrophysics 659 (March 2022): A42. http://dx.doi.org/10.1051/0004-6361/202142571.
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Context. Magnetically and thermally driven disk winds have gained popularity in the light of the current paradigm of low viscosities in protoplanetary disks that nevertheless present large accretion rates even in the presence of inner cavities. The possibility of dust entrainment in these winds may explain recent scattered light observations and constitutes a way of dust transport towards outer regions of the disk. Aims. We aim to study the dust dynamics in these winds and explore the differences between photoevaporation and magnetically driven disk winds in this regard. We quantify maximum entrainable grain sizes, the flow angle, and the general detectability of such dusty winds. Methods. We used the FARGO3D code to perform global, 2.5D axisymmetric, nonideal MHD simulations including ohmic and ambipolar diffusion. Dust was treated as a pressureless fluid. Synthetic observations were created with the radiative transfer code RADMC-3D. Results. We find a significant difference in the dust entrainment efficiency of warm, ionized winds such as photoevaporation and magnetic winds including X-ray and extreme ultraviolet heating compared to cold magnetic winds. The maximum entrainable grain size varies from 3 μm−6 μm for ionized winds to 1 μm for cold magnetic winds. The dust flow angle decreases rapidly with increasing grain size. Dust grains in cold magnetic winds tend to flow along a shallower angle compared to the warm, ionized winds. With increasing distance to the central star, the dust entrainment efficiency decreases. Larger values of the turbulent viscosity increase the maximum grain size radius of possible dust entrainment. Our simulations indicate that diminishing dust content in the outer regions of the wind can be mainly attributed to the dust settling in the disk. The Stokes number along the wind launching front stays constant in the outer region. In the synthetic images, the dusty wind appears as a faint, conical emission region which is brighter for a cold magnetic wind.
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Bilal, Muhammad, Yngve Birkelund, and Matthew Homola. "High Winds at Nygårdsfjell." Journal of Clean Energy Technologies 3, no. 2 (2015): 106–9. http://dx.doi.org/10.7763/jocet.2015.v3.176.
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Koo, Bon-Chul, and Christopher F. McKee. "Dynamics of wind bubbles and superbubbles. I - Slow winds and fast winds. II - Analytic theory." Astrophysical Journal 388 (March 1992): 93. http://dx.doi.org/10.1086/171132.
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Massa, Derek, and Raman K. Prinja. "UV Wind Variability in B Supergiants and its Implications for Wind Structures." International Astronomical Union Colloquium 169 (1999): 214–17. http://dx.doi.org/10.1017/s0252921100072018.
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AbstractWe discuss why B supergiant winds are particularly well suited for wind studies, and present or refer to dynamic spectra which suggest the presence of disks, bifurcated winds, shock formation, rotationally modulated winds and the spontaneous generation of wind enhancements. They underscore the strength and richness of wind variability in B supergiants and the challenges these phenomena present to theoretical studies of stellar winds.
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Matt, Sean, and Ralph E. Pudritz. "The nature of stellar winds in the star-disk interaction." Proceedings of the International Astronomical Union 3, S243 (May 2007): 299–306. http://dx.doi.org/10.1017/s1743921307009659.
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AbstractStellar winds may be important for angular momentum transport from accreting T Tauri stars, but the nature of these winds is still not well-constrained. We present some simulation results for hypothetical, hot (∼ 106 K) coronal winds from T Tauri stars, and we calculate the expected emission properties. For the high mass loss rates required to solve the angular momentum problem, we find that the radiative losses will be much greater than can be powered by the accretion process. We place an upper limit to the mass loss rate from accretion-powered coronal winds of ∼ 10−11M yr−1. We conclude that accretion powered stellar winds are still a promising scenario for solving the stellar angular momentum problem, but the winds must be cool (e.g., 104 K) and thus are not driven by thermal pressure.
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Feng, Chengfeng, and Zhaoxia Pu. "The impacts of assimilating Aeolus horizontal line-of-sight winds on numerical predictions of Hurricane Ida (2021) and a mesoscale convective system over the Atlantic Ocean." Atmospheric Measurement Techniques 16, no. 10 (June 1, 2023): 2691–708. http://dx.doi.org/10.5194/amt-16-2691-2023.
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Abstract. The Aeolus satellite, the first spaceborne wind lidar launched by the European Space Agency (ESA) on 22 August 2018, provides global measurements of horizontal line-of-sight (HLOS) winds. The assimilation of Aeolus HLOS winds has been proven to improve numerical weather predictions (NWPs). Still, its influences on forecasts of tropical cyclones (TCs) and tropical convective systems have yet to be examined in detail. This study investigates the impacts of assimilating Aeolus HLOS winds on the analysis and forecasts of Hurricane Ida (2021) and a mesoscale convective system (MCS) embedded in an African easterly wave (AEW) over the Atlantic Ocean (AO) with the mesoscale community Weather Research and Forecasting (WRF) model and the NCEP Gridpoint Statistical Interpolation (GSI)-based three-dimensional ensemble-variational (3DEnVAR) hybrid data assimilation (DA) system. Mie-cloudy and Rayleigh-clear winds are assimilated. The results for Ida (2021) show that assimilating Aeolus HLOS winds leads to better track predictions. The intensity forecasts are improved in some cases, even with limited coverage of Aeolus HLOS winds within the inner core region of Ida (2021). In addition, the structure of heavy precipitation associated with Ida (2021) is refined after the assimilation of Aeolus HLOS winds. Further diagnosis demonstrates that the improved intensity and precipitation forecasts result from enhanced divergence in the upper level of the troposphere after the assimilation of Aeolus HLOS winds. Additional results from the MCS associated with an AEW indicate that assimilating Aeolus HLOS winds enhances forecasts of its precipitation structure and the associated low-level divergence. Findings from this study suggest that the assimilation of Aeolus HLOS winds has the potential to improve forecasts for TCs and tropical convective systems.
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Ricciardulli, Lucrezia, and Frank J. Wentz. "A Scatterometer Geophysical Model Function for Climate-Quality Winds: QuikSCAT Ku-2011." Journal of Atmospheric and Oceanic Technology 32, no. 10 (October 2015): 1829–46. http://dx.doi.org/10.1175/jtech-d-15-0008.1.
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AbstractSpace-based observations of ocean surface winds have been available for more than 25 years. To combine the observations from multiple sensors into one record with the accuracy required for climate studies requires a consistent methodology and calibration standard for the various instruments. This study describes a new geophysical model function (GMF) specifically developed for preparing the QuikSCAT winds to serve as a backbone of an ocean vector wind climate data record. This paper describes the methodology used and presents the quality of the reprocessed winds. The new Ku-2011 model function was developed using WindSat winds as a calibration truth. An extensive validation of the Ku-2011 winds was performed that focused on 1) proving the consistency of satellite winds from different sensors at all wind speed regimes; 2) exploring and understanding possible sources of bias in the QuikSCAT retrievals; 3) validating QuikSCAT wind speeds versus in situ observations, and comparing observed wind directions versus those from numerical models; 4) comparing satellite observations of high wind speeds with measurements obtained from aircraft flying into storms; 5) analyzing case studies of satellite-based observations of winds in tropical storms; and 6) illustrating how rain impacts QuikSCAT wind speed retrievals. The results show that the reprocessed QuikSCAT data are greatly improved in both speed and direction at high winds. Finally, there is a discussion on how these QuikSCAT results fit into a long-term effort toward creating a climate data record of ocean vector winds.
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Coleman, Timothy A., and Kevin R. Knupp. "Factors Affecting Surface Wind Speeds in Gravity Waves and Wake Lows." Weather and Forecasting 24, no. 6 (December 1, 2009): 1664–79. http://dx.doi.org/10.1175/2009waf2222248.1.
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Abstract Ducted gravity waves and wake lows have been associated with numerous documented cases of “severe” winds (>25 m s−1) and wind damage. These winds are associated with the pressure perturbations and transient mesoscale pressure gradients occurring in many gravity waves and wake lows. However, not all wake lows and gravity waves produce significant winds nor wind damage. In this paper, the factors that affect the surface winds produced by ducted gravity waves and wake lows are reviewed and examined. It is shown theoretically that the factors most conducive to high surface winds include a large-amplitude pressure disturbance, a slow intrinsic speed of propagation, and an ambient wind with the same sign as the pressure perturbation (i.e., a headwind for a pressure trough). Multiple case studies are presented, contrasting gravity waves and wake lows with varying amplitudes, intrinsic speeds, and background winds. In some cases high winds occurred, while in others they did not. In each case, the factor(s) responsible for significant winds, or the lack thereof, are discussed. It is hoped that operational forecasters will be able to, in some cases, compute these factors in real time, to ascertain in more detail the threat of damaging wind from an approaching ducted gravity wave or wake low.
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Chang, Pao-Liang, and Pin-Fang Lin. "Radar Anomalous Propagation Associated with Foehn Winds Induced by Typhoon Krosa (2007)." Journal of Applied Meteorology and Climatology 50, no. 7 (July 2011): 1527–42. http://dx.doi.org/10.1175/2011jamc2619.1.
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AbstractIn this study, unusual radar anomalous propagation (AP) phenomena associated with foehn winds induced by Typhoon Krosa (2007) were documented by using observations from radar, surface stations, and soundings. The AP echoes embedded within rainband areas and exhibited inward motions toward the radar site within 2–3 h prior to the occurrences of foehn winds at the radar site, which would interfere with the interpretation of radar data and associated downstream applications. As Typhoon Krosa appeared in the vicinity of the northeastern coast of Taiwan, foehn winds with significant subsidence warming and drying generated by downslope winds were observed in southeastern Taiwan. The foehn winds continuously moved northward within confined areas from the southeastern to eastern–central parts of Taiwan. Before the foehn winds penetrated to the surface, the subsidence warming introduced a temperature inversion layer above the surface and caused the ducting of radar beams. Analyses of refractive index and ray tracing suggested that the occurrence and evolution of the AP echoes during Typhoon Krosa were closely related to the varying inversion heights induced by downslope winds.
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Pisso, I., V. Marécal, B. Legras, and G. Berthet. "Sensitivity of ensemble Lagrangian reconstructions to assimilated wind time step resolution." Atmospheric Chemistry and Physics 10, no. 7 (April 1, 2010): 3155–62. http://dx.doi.org/10.5194/acp-10-3155-2010.
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Abstract. We study the impact of temporal and spatial resolution and changes in modelled meteorological winds in the context of diffusive ensemble Lagrangian reconstructions. In situ tracer measurements are modelled based on coarse resolution global 3-D tracer distributions from a chemistry-transport model and on different time series of meteorological wind fields including a special set of 1-hourly analysed winds which is compared with 3 and 6-hourly operational analysed winds and with 3-hourly ERA-interim reanalysis. Increasing the time resolution of the advecting winds from three to one hour using the operational winds provides an improvement on diffusive reconstructions in the period studied but smaller than that obtained from six to three hours. The positive impact of using 1-hourly winds is similar to that obtained using ERA-Interim 3-hourly winds instead of the 3-hourly ECMWF operational analysis for the same period. This study sets out a technique to quantify differences in time series of meteorological wind fields here applied to assess the optimal space and time resolutions for ensemble Lagrangian reconstructions in the lower stratosphere.
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Middleton, H. R., N. J. Mitchell, and H. G. Muller. "Mean winds of the mesosphere and lower thermosphere at 52° N in the period 1988–2000." Annales Geophysicae 20, no. 1 (January 31, 2002): 81–91. http://dx.doi.org/10.5194/angeo-20-81-2002.
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Abstract. A meteor radar in the UK (near 52° N) has been used to measure the mean winds of the mesosphere/lower-thermosphere (MLT) region over the period 1988–2000. The seasonal course and interannual variability is characterised and comparisons are made with a number of models. Annual mean wind trends were found to be + 0.37 ms-1 yr-1 for the zonal component and + 0.157 ms-1 yr-1 for the meridional component. Seasonal means revealed significant trends in the case of meridional winds in spring ( + 0.38 ms-1 yr-1) and autumn ( + 0.29 ms-1 yr-1), and zonal winds in summer ( + 0.48 ms-1 yr-1) and autumn ( + 0.38 ms-1 yr-1). Significant correlation coefficients, R, between the sunspot number and seasonal mean wind are found in four instances. In the case of the summer zonal winds, R = + 0.732; for the winter meridional winds, R = - 0.677; for the winter zonal winds, R = - 0.472; and for the autumn zonal winds R = + 0.508.Key words. Meteorology and atmospheric dynamics (climatology; general circulation; middle atmospheric dynamics)
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Vogt-Vincent, Noam S., and Helen L. Johnson. "Multidecadal and climatological surface current simulations for the southwestern Indian Ocean at 1∕50° resolution." Geoscientific Model Development 16, no. 3 (February 16, 2023): 1163–78. http://dx.doi.org/10.5194/gmd-16-1163-2023.
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Abstract. The Western INDian Ocean Simulation (WINDS) is a regional configuration of the Coastal and Regional Ocean Community Model (CROCO) for the southwestern Indian Ocean. WINDS has a horizontal resolution of 1/50∘ (∼2 km) and spans a latitudinal range of 23.5∘ S–0∘ N and a longitudinal range from the East African coast to 77.5∘ E. We ran two experiments using the WINDS configuration: WINDS-M, a full 28-year multidecadal run (1993–2020); and WINDS-C, a 10-year climatological control run with monthly climatological forcing. WINDS was primarily run for buoyant Lagrangian particle tracking applications, and horizontal surface velocities are output at a temporal resolution of 30 min. Other surface fields are output daily, and the full 3D temperature, salinity, and velocity fields are output every 5 d. We demonstrate that WINDS successfully manages to reproduce surface temperature, salinity, currents, and tides in the southwestern Indian Ocean, and it is therefore appropriate for use in regional marine dispersal studies for buoyant particles or other applications using high-resolution surface ocean properties.