Journal articles: 'Finescale'

1

Polzin, Kurt L., John M. Toole, and Raymond W. Schmitt. "Finescale Parameterizations of Turbulent Dissipation." Journal of Physical Oceanography 25, no. 3 (March 1995): 306–28. http://dx.doi.org/10.1175/1520-0485(1995)025<0306:fpotd>2.0.co;2.

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Polzin, Kurt L., Alberto C. Naveira Garabato, Tycho N. Huussen, Bernadette M. Sloyan, and Stephanie Waterman. "Finescale parameterizations of turbulent dissipation." Journal of Geophysical Research: Oceans 119, no. 2 (February 2014): 1383–419. http://dx.doi.org/10.1002/2013jc008979.

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De Lannoy, Gabriëlle J. M., Rolf H. Reichle, Paul R. Houser, Kristi R. Arsenault, Niko E. C. Verhoest, and Valentijn R. N. Pauwels. "Satellite-Scale Snow Water Equivalent Assimilation into a High-Resolution Land Surface Model." Journal of Hydrometeorology 11, no. 2 (April 1, 2010): 352–69. http://dx.doi.org/10.1175/2009jhm1192.1.

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Abstract Four methods based on the ensemble Kalman filter (EnKF) are tested to assimilate coarse-scale (25 km) snow water equivalent (SWE) observations (typical of passive microwave satellite retrievals) into finescale (1 km) land model simulations. Synthetic coarse-scale observations are assimilated directly using an observation operator for mapping between the coarse and fine scales or, alternatively, after disaggregation (regridding) to the finescale model resolution prior to data assimilation. In either case, observations are assimilated either simultaneously or independently for each location. Results indicate that assimilating disaggregated finescale observations independently (method 1D-F1) is less efficient than assimilating a collection of neighboring disaggregated observations (method 3D-Fm). Direct assimilation of coarse-scale observations is superior to a priori disaggregation. Independent assimilation of individual coarse-scale observations (method 3D-C1) can bring the overall mean analyzed field close to the truth, but does not necessarily improve estimates of the finescale structure. There is a clear benefit to simultaneously assimilating multiple coarse-scale observations (method 3D-Cm) even as the entire domain is observed, indicating that underlying spatial error correlations can be exploited to improve SWE estimates. Method 3D-Cm avoids artificial transitions at the coarse observation pixel boundaries and can reduce the RMSE by 60% when compared to the open loop in this study.

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Vali, Gabor, Robert D. Kelly, Jeffrey French, Samuel Haimov, David Leon, Robert E. McIntosh, and Andrew Pazmany. "Finescale Structure and Microphysics of Coastal Stratus." Journal of the Atmospheric Sciences 55, no. 24 (December 1998): 3540–64. http://dx.doi.org/10.1175/1520-0469(1998)055<3540:fsamoc>2.0.co;2.

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Straka, Jerry M., Erik N. Rasmussen, and Sherman E. Fredrickson. "A Mobile Mesonet for Finescale Meteorological Observations." Journal of Atmospheric and Oceanic Technology 13, no. 5 (October 1996): 921–36. http://dx.doi.org/10.1175/1520-0426(1996)013<0921:ammffm>2.0.co;2.

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Diekmann, Martin, Cecilia Dupre, and Eddy Maarel. "Finescale species associations in alvar limestone grasslands." Nordic Journal of Botany 23, no. 1 (March 2003): 115–28. http://dx.doi.org/10.1111/j.1756-1051.2003.tb00373.x.

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Girard, Claude, Robert Benoit, and Michel Desgagné. "Finescale Topography and the MC2 Dynamics Kernel." Monthly Weather Review 133, no. 6 (June 1, 2005): 1463–77. http://dx.doi.org/10.1175/mwr2931.1.

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Abstract The Canadian Mesoscale Compressible Community (MC2) model provided daily forecasts across the Alps at 3-km resolution during the Mesoscale Alpine Programme (MAP) field phase of 1999. Among the results of this endeavor, some have had an immediate impact on MC2 itself as it increasingly became evident that the model was spuriously too sensitive to finescale orographic forcing. The model solves the Euler equations of motion using a semi-implicit semi-Lagrangian scheme in an oblique terrain-following coordinate. To improve model behavior, typical approaches were tried at first. These included a generalization of the coordinate transformation to make the terrain influence decay much more quickly with height as well as the introduction of nonisothermal basic states to diminish the amplitude of numerical truncation errors. The concept of piecewise-constant finite elements was invoked to reduce coding arbitrariness. But it was later pointed out that the problem was very specific and due to a numerical inconsistency. The true height of model grid points is fixed and known in height-based coordinates. Nevertheless, it was discovered that for this semi-Lagrangian scheme to be consistent, the departure height is an unknown that must be obtained in the same manner as the other unknowns.

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Fridley, Jason D. "Downscaling Climate over Complex Terrain: High Finescale (<1000 m) Spatial Variation of Near-Ground Temperatures in a Montane Forested Landscape (Great Smoky Mountains)*." Journal of Applied Meteorology and Climatology 48, no. 5 (May 1, 2009): 1033–49. http://dx.doi.org/10.1175/2008jamc2084.1.

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Abstract Landscape-driven microclimates in mountainous terrain pose significant obstacles to predicting the response of organisms to atmospheric warming, but few if any studies have documented the extent of such finescale variation over large regions. This paper demonstrates that ground-level temperature regimes in Great Smoky Mountains National Park (Tennessee and North Carolina) vary considerably over fine spatial scales and are only partially linked to synoptic weather patterns and environmental lapse rates. A 120-sensor network deployed across two watersheds in 2005–06 exhibited finescale (<1000-m extent) temperature differences of over 2°C for daily minima and over 4°C for daily maxima. Landscape controls over minimum temperatures were associated with finescale patterns of soil moisture content, and maximum temperatures were associated with finescale insolation differences caused by topographic exposure and vegetation cover. By linking the sensor array data to 10 regional weather stations and topographic variables describing site radiation load and moisture content, multilevel spatial models of 30-m resolution were constructed to map daily temperatures across the 2090-km2 park, validated with an independent 50-sensor network. Maps reveal that different landscape positions do not maintain relative differences in temperature regimes across seasons. Near-stream locations are warmer in the winter and cooler in the summer, and sites of low elevation more closely track synoptic weather patterns than do wetter high-elevation sites. This study suggests a strong interplay between near-ground heat and water balances and indicates that the influence of past and future shifts in regional temperatures on the park’s biota may be buffered by soil moisture surfeits from high regional rainfall.

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Whalen, Caitlin B., Jennifer A. MacKinnon, Lynne D. Talley, and Amy F. Waterhouse. "Estimating the Mean Diapycnal Mixing Using a Finescale Strain Parameterization." Journal of Physical Oceanography 45, no. 4 (April 2015): 1174–88. http://dx.doi.org/10.1175/jpo-d-14-0167.1.

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AbstractFinescale methods are currently being applied to estimate the mean turbulent dissipation rate and diffusivity on regional and global scales. This study evaluates finescale estimates derived from isopycnal strain by comparing them with average microstructure profiles from six diverse environments including the equator, above ridges, near seamounts, and in strong currents. The finescale strain estimates are derived from at least 10 nearby Argo profiles (generally <60 km distant) with no temporal restrictions, including measurements separated by seasons or decades. The absence of temporal limits is reasonable in these cases, since the authors find the dissipation rate is steady over seasonal time scales at the latitudes being considered (0°–30° and 40°–50°). In contrast, a seasonal cycle of a factor of 2–5 in the upper 1000 m is found under storm tracks (30°–40°) in both hemispheres. Agreement between the mean dissipation rate calculated using Argo profiles and mean from microstructure profiles is within a factor of 2–3 for 96% of the comparisons. This is both congruous with the physical scaling underlying the finescale parameterization and indicates that the method is effective for estimating the regional mean dissipation rates in the open ocean.

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Dematteis, Giovanni, Kurt Polzin, and Yuri V. Lvov. "On the Origins of the Oceanic Ultraviolet Catastrophe." Journal of Physical Oceanography 52, no. 4 (April 2022): 597–616. http://dx.doi.org/10.1175/jpo-d-21-0121.1.

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Abstract We provide a first-principles analysis of the energy fluxes in the oceanic internal wave field. The resulting formula is remarkably similar to the renowned phenomenological formula for the turbulent dissipation rate in the ocean, which is known as the finescale parameterization. The prediction is based on the wave turbulence theory of internal gravity waves and on a new methodology devised for the computation of the associated energy fluxes. In the standard spectral representation of the wave energy density, in the two-dimensional vertical wavenumber–frequency (m–ω) domain, the energy fluxes associated with the steady state are found to be directed downscale in both coordinates, closely matching the finescale parameterization formula in functional form and in magnitude. These energy transfers are composed of a “local” and a “scale-separated” contributions; while the former is quantified numerically, the latter is dominated by the induced diffusion process and is amenable to analytical treatment. Contrary to previous results indicating an inverse energy cascade from high frequency to low, at odds with observations, our analysis of all nonzero coefficients of the diffusion tensor predicts a direct energy cascade. Moreover, by the same analysis fundamental spectra that had been deemed “no-flux” solutions are reinstated to the status of “constant-downscale-flux” solutions. This is consequential for an understanding of energy fluxes, sources, and sinks that fits in the observational paradigm of the finescale parameterization, solving at once two long-standing paradoxes that had earned the name of “oceanic ultraviolet catastrophe.” Significance Statement The global circulation models cannot resolve the scales of the oceanic internal waves. The finescale parameterization of turbulent dissipation, a formula grounded in observations, is the standard tool by which the energy transfers due to internal waves are incorporated in the global models. Here, we provide an interpretation of this parameterization formula building on the first-principles statistical theory describing energy transfers between waves at different scales. Our result is in agreement with the finescale parameterization and points out a large contribution to the energy fluxes due to a type of wave interactions (local) usually disregarded. Moreover, the theory on which the traditional understanding of the parameterization is mainly built, a “diffusion approximation,” is known to be partly in contradiction with observations. We put forward a solution to this problem, visualized by means of “streamlines” that improve the intuition of the direction of the energy cascade.

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Radko, Timour, and Melvin E. Stern. "Finescale Instabilities of the Double-Diffusive Shear Flow*." Journal of Physical Oceanography 41, no. 3 (March 1, 2011): 571–85. http://dx.doi.org/10.1175/2010jpo4459.1.

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Abstract This study examines dynamics of finescale instabilities in thermohaline–shear flows. It is shown that the presence of the background diapycnal temperature and salinity fluxes due to double diffusion has a destabilizing effect on the basic current. Using linear stability analysis based on the Floquet theory for the sinusoidal basic velocity profile, the authors demonstrate that the well-known Richardson number criterion (Ri < ¼) cannot be directly applied to doubly diffusive fluids. Rigorous instabilities are predicted to occur for Richardson numbers as high as—or even exceeding—unity. The inferences from the linear theory are supported by the fully nonlinear numerical simulations. Since the Richardson number in the main thermocline rarely drops below ¼, whereas the observations of turbulent patches are common, the authors hypothesize that some turbulent mixing events can be attributed to the finescale instabilities associated with double-diffusive processes.

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12

Parsons, David B., Melvyn A. Shapiro, R. Michael Hardesty, Robert J. Zamora, and Janet M. Intrieri. "The Finescale Structure of a West Texas Dryline." Monthly Weather Review 119, no. 5 (May 1991): 1242–58. http://dx.doi.org/10.1175/1520-0493(1991)119<1242:tfsoaw>2.0.co;2.

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Krueger, Steven K., Chwen-Wei Su, and Patrick A. McMurtry. "Modeling Entrainment and Finescale Mixing in Cumulus Clouds." Journal of the Atmospheric Sciences 54, no. 23 (December 1997): 2697–712. http://dx.doi.org/10.1175/1520-0469(1997)054<2697:meafmi>2.0.co;2.

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14

Polzin, Kurt, Eric Kunze, Jules Hummon, and Eric Firing. "The Finescale Response of Lowered ADCP Velocity Profiles." Journal of Atmospheric and Oceanic Technology 19, no. 2 (February 2002): 205–24. http://dx.doi.org/10.1175/1520-0426(2002)019<0205:tfrola>2.0.co;2.

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15

Wurman, Joshua, and Karen Kosiba. "Finescale Radar Observations of Tornado and Mesocyclone Structures." Weather and Forecasting 28, no. 5 (October 1, 2013): 1157–74. http://dx.doi.org/10.1175/waf-d-12-00127.1.

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Abstract A variety of vortex configurations observed at finescale with Doppler On Wheels (DOW) radars in and near the hook echoes of supercell thunderstorms are described. These include marginal/weak tornadoes, often with no documented condensation funnels, debris rings, or low-reflectivity eyes; multiple-vortex mesocyclones; multiple simultaneous tornadoes; satellite tornadoes; cyclonic–anticyclonic tornado pairs; multiple vortices within other multiple vortices; tornadoes with quasi-concentric multiple wind field maxima; lines of vortices outside tornadoes; and horizontal vortices. The kinematic structures of these different phenomena are documented and compared. The process of multiple vortex circulations evolving from and into tornadoes is documented. DOW observations suggest that there is no clear spatial-scale separation between multiple-vortex tornadoes and larger multiple-vortex circulations. These different vortex configurations motivate a refined definition of what constitutes a tornado, excluding many multiple, weak, embedded, and tornado-associated vortices.

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Yang, Muqun, Robert M. Rauber, and Mohan K. Ramamurthy. "Origin, Evolution, and Finescale Structure of the St. Valentine’s Day Mesoscale Gravity Wave Observed during STORM-FEST. Part II: Finescale Structure." Monthly Weather Review 129, no. 2 (February 2001): 218–36. http://dx.doi.org/10.1175/1520-0493(2001)129<0218:oeafso>2.0.co;2.

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Fine, Elizabeth C., Matthew H. Alford, Jennifer A. MacKinnon, and John B. Mickett. "Microstructure Mixing Observations and Finescale Parameterizations in the Beaufort Sea." Journal of Physical Oceanography 51, no. 1 (January 2021): 19–35. http://dx.doi.org/10.1175/jpo-d-19-0233.1.

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AbstractIn the Beaufort Sea in September of 2015, concurrent mooring and microstructure observations were used to assess dissipation rates in the vicinity of 72°35′N, 145°1′W. Microstructure measurements from a free-falling profiler survey showed very low [(10−10) W kg−1] turbulent kinetic energy dissipation rates ε. A finescale parameterization based on both shear and strain measurements was applied to estimate the ratio of shear to strain Rω and ε at the mooring location, and a strain-based parameterization was applied to the microstructure survey (which occurred approximately 100 km away from the mooring site) for direct comparison with microstructure results. The finescale parameterization worked well, with discrepancies ranging from a factor of 1–2.5 depending on depth. The largest discrepancies occurred at depths with high shear. Mean Rω was 17, and Rω showed high variability with values ranging from 3 to 50 over 8 days. Observed ε was slightly elevated (factor of 2–3 compared with a later survey of 11 profiles taken over 3 h) from 25 to 125 m following a wind event which occurred at the beginning of the mooring deployment, reaching a maximum of ε= 6 × 10−10 W kg−1 at 30-m depth. Velocity signals associated with near-inertial waves (NIWs) were observed at depths greater than 200 m, where the Atlantic Water mass represents a reservoir of oceanic heat. However, no evidence of elevated ε or heat fluxes was observed in association with NIWs at these depths in either the microstructure survey or the finescale parameterization estimates.

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Hohreiter, Vincent. "Finescale Structure and Dynamics of an Atmospheric Temperature Interface." Journal of the Atmospheric Sciences 65, no. 5 (May 1, 2008): 1701–10. http://dx.doi.org/10.1175/2007jas2576.1.

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Abstract Near-ground observations of an atmospheric temperature interface in the stable nocturnal boundary layer are reported. The thermal effect of the interface passage was a 5-K decrease in temperature during a 5-min period in which changes in wind speed and wind direction were also observed. The interface is of unknown origin and horizontal and vertical scale. A 32-Hz time series of temperature measured with a sonic anemometer–thermometer at 1.5 m above ground level revealed a sharp, nonintermittent decrease in temperature (∼1 K s−1) nested within a more gradual, intermittent decrease (∼1 K min−1). A first attempt to extricate this subtle feature with regard to the relevant physics of generalized density currents is presented. It is shown that a very similar feature has been observed in the literature, but not interpreted for its physical significance. The contribution of this paper is its unique interpretation of the high-resolution temperature time series as it corresponds to the finescale physical character of an interface of density or temperature, and the motion of such an interface along the ground. Parameters of interest, including a spatial temperature gradient normal to the interface (∼1 K m−1), an interfacial thickness (2.8 m), and a thermal boundary layer for the interface (288 m), are calculated. Additionally, theoretical and empirical arguments are presented for a viscous suppression of turbulent mixing in the immediate vicinity of an interface of density or temperature.

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Lewellen, D. C., Baiyun Gong, and W. S. Lewellen. "Effects of Finescale Debris on Near-Surface Tornado Dynamics." Journal of the Atmospheric Sciences 65, no. 10 (October 2008): 3247–62. http://dx.doi.org/10.1175/2008jas2686.1.

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Debris clouds provide an important visual signature of tornadoes and can potentially significantly affect the wind structure, damage potential, and Doppler radar measurements of tornado wind speeds. To study such issues, the dynamics of finescale debris have been added to an existing high-resolution large-eddy simulation model of tornado dynamics. A so-called “two-fluid” or “Eulerian–Eulerian” approach is employed, together with a surface layer model for lofting and depositing debris. In this paper the debris implementation is described, three critical dimensionless parameters governing tornado debris effects are identified, and sample results from a large set of simulations of tornadoes with idealized debris are presented. The results demonstrate that the accumulation of small-scale debris within the surface layer and corner flow can significantly alter the wind speeds and flow structure of the tornado vortex within a few hundred meters of the surface. They suggest that the total mass of the debris cloud can reach tens of thousands of tons. Near the surface, the debris mass loading can be well above 1, the peak mean velocities can be reduced by as much as half, and the total momentum (air plus debris) can either significantly increase or decrease. Local air and debris velocities can differ significantly and in a nontrivial fashion, thereby complicating the interpretation of Doppler radar measurements of tornado structure. Debris fluctuations, centrifuging, negative buoyancy, and angular momentum transport are all significant mechanisms for the debris effects. A negative physical feedback reduces the sensitivity of the results to changes in the parameterization of the surface debris fluxes. The realistic simulation of tornado debris clouds and surface damage tracks should prove useful in identifying the dynamics governing their observed counterparts.

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Ronda, R. J., G. J. Steeneveld, B. G. Heusinkveld, J. J. Attema, and A. A. M. Holtslag. "Urban Finescale Forecasting Reveals Weather Conditions with Unprecedented Detail." Bulletin of the American Meteorological Society 98, no. 12 (December 1, 2017): 2675–88. http://dx.doi.org/10.1175/bams-d-16-0297.1.

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Abstract Urban landscapes impact the lives of urban dwellers by influencing local weather conditions. However, weather forecasting down to the street and neighborhood scale has been beyond the capabilities of numerical weather prediction (NWP) despite the fact that observational systems are now able to monitor urban climate at these scales. In this study, weather forecasts at intra-urban scales were achieved by exploiting recent advances in topographic element mapping and aerial photography as well as looking at detailed mappings of soil characteristics and urban morphological properties, which were subsequently incorporated into a specifically adapted Weather Research and Forecasting (WRF) Model. The urban weather forecasting system (UFS) was applied to the Amsterdam, Netherlands, metropolitan area during the summer of 2015, where it produced forecasts for the city down to the neighborhood level (a few hundred meters). Comparing these forecasts to the dense network of urban weather station observations within the Amsterdam metropolitan region showed that the forecasting system successfully determined the impact of urban morphological characteristics and urban spatial structure on local temperatures, including the cooling effect of large water bodies on local urban temperatures. The forecasting system has important practical applications for end users such as public health agencies, local governments, and energy companies. It appears that the forecasting system enables forecasts of events on a neighborhood level where human thermal comfort indices exceeded risk thresholds during warm weather episodes. These results prove that worldwide urban weather forecasting is within reach of NWP, provided that appropriate data and computing resources become available to ensure timely and efficient forecasts.

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Toole, John M. "Temporal Characteristics of Abyssal Finescale Motions above Rough Bathymetry." Journal of Physical Oceanography 37, no. 3 (March 1, 2007): 409–27. http://dx.doi.org/10.1175/jpo2988.1.

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Abstract Current-meter data from a two-year mooring within a fracture zone on the western flank of the Mid-Atlantic Ridge in the South Atlantic Ocean are reported. The mooring, deployed in conjunction with the Brazil Basin Tracer Release Experiment, was placed in the general area where enhanced diapycnal mixing had previously been inferred. The current-meter data characterize the velocity, temperature, shear, and temperature gradient variability as a function of frequency. Energetic velocities and shears were observed at the mooring at a variety of frequencies. In addition to semidiurnal flows, a significant amount of shear variance derived from near-inertial motions, as has been seen in a recent numerical modeling study of tidal-frequency internal wave radiation and wave–wave interaction. At times, a fortnightly modulation of the total superinertial shear variance was indicated in the data, but this signal did not dominate the records. Wave ray tracing indicates that the deeper current meters may have been placed in a shadow zone for locally generated internal tides. At shallower levels, it is suggested that dispersion, wave–wave interaction, and wave breaking effectively obscured the sources of the finescale energy. Average diapycnal diffusivity estimates inferred from a Richardson-number-based parameterization and from observations of temperature inversions at 4648 m were of the same order of magnitude as those derived from turbulent dissipation estimates and from the rate of diapycnal tracer dispersion. The mooring data thus add additional support to the idea that energetic finescale motions above rough bathymetry support enhanced turbulent diapycnal mixing in these regions.

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Charba, Jerome P., Frederick G. Samplatsky, Andrew J. Kochenash, Phillip E. Shafer, Judy E. Ghirardelli, and Chenjie Huang. "LAMP Upgraded Convection and Total Lightning Probability and “Potential” Guidance for the Conterminous United States." Weather and Forecasting 34, no. 5 (October 1, 2019): 1519–45. http://dx.doi.org/10.1175/waf-d-19-0015.1.

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Abstract Localized Aviation MOS Program (LAMP) convection and lightning probability and “potential” guidance forecasts for the conterminous United States, developed by the Meteorological Development Laboratory (MDL), have been produced operationally and made available to aviation and other users through the National Digital Guidance Database (NDGD) since April 2014. In response to user requests for improved skill and resolution of these forecasts, MDL has recently made extensive upgrades, and a switch to the new LAMP guidance was made in January 2018. Upgrades include improved spatial and temporal resolution of the predictands, which were enabled by first time LAMP use of finescale radar reflectivity products from the Multi-Radar Multi-Sensor (MRMS) system, total lightning observations from a ground-based lightning sensing system, and finescale model output from the High Resolution Rapid Refresh (HRRR) model. This article describes how these new data inputs are applied in the LAMP model to obtain improved skill and sharpness of the convection and total lightning probability forecasts. Strengths and limitations in LAMP performance are shown through verification statistics and example verification maps for a selected intense convective storm case.

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Lawrence, Dale A., and Ben B. Balsley. "High-Resolution Atmospheric Sensing of Multiple Atmospheric Variables Using the DataHawk Small Airborne Measurement System." Journal of Atmospheric and Oceanic Technology 30, no. 10 (October 1, 2013): 2352–66. http://dx.doi.org/10.1175/jtech-d-12-00089.1.

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Abstract The DataHawk small airborne measurement system provides in situ atmospheric measurement capabilities for documenting scales as small as 1 m and can access reasonably large volumes in and above the atmospheric boundary layer at low cost. The design of the DataHawk system is described, beginning with the atmospheric measurement requirements, and articulating five key challenges that any practical measurement system must overcome. The resulting characteristics of the airborne and ground support components of the DataHawk system are outlined, along with its deployment, operating, and recovery modes. Typical results are presented to illustrate the types and quality of data provided by the current system, as well as the need for more of these finescale measurements. Particular focus is given to the DataHawk's ability to make very-high-resolution measurements of a variety of atmospheric variables simultaneously, with emphasis given to the measurement of two important finescale turbulence parameters, (the temperature turbulence structure constant) and ɛ (the turbulent energy dissipation rate). Future sensing possibilities and limitations using this approach are also discussed.

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Chao, Yi, Zhijin Li, John D. Farrara, and Peter Hung. "Blending Sea Surface Temperatures from Multiple Satellites and In Situ Observations for Coastal Oceans." Journal of Atmospheric and Oceanic Technology 26, no. 7 (July 1, 2009): 1415–26. http://dx.doi.org/10.1175/2009jtecho592.1.

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Abstract A two-dimensional variational data assimilation (2DVAR) method for blending sea surface temperature (SST) data from multiple observing platforms is presented. This method produces continuous fields and has the capability of blending multiple satellite and in situ observations. In addition, it allows specification of inhomogeneous and anisotropic background correlations, which are common features of coastal ocean flows. High-resolution (6 km in space and 6 h in time) blended SST fields for August 2003 are produced for a region off the California coast to demonstrate and evaluate the methodology. A comparison of these fields with independent observations showed root-mean-square errors of less than 1°C, comparable to the errors in conventional SST observations. The blended SST fields also clearly reveal the finescale spatial and temporal structures associated with coastal upwelling, demonstrating their utility in the analysis of finescale flows. With the high temporal resolution, the blended SST fields are also used to describe the diurnal cycle. Potential applications of this SST blending methodology in other coastal regions are discussed.

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Liu, Lei, and Fei Hu. "Finescale Clusterization Intermittency of Turbulence in the Atmospheric Boundary Layer." Journal of the Atmospheric Sciences 77, no. 7 (July 1, 2020): 2375–92. http://dx.doi.org/10.1175/jas-d-19-0270.1.

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AbstractThe intermittency of atmospheric turbulence plays an important role in the understanding of particle dispersal in the atmospheric boundary layer and in the statistical simulation of high-frequency wind speed in various applications. There are two kinds of intermittency, namely, the magnitude intermittency (MI) related to non-Gaussianity and the less studied clusterization intermittency (CI) related to long-term correlation. In this paper, we use a 20 Hz ultrasonic dataset lasting for 1 month to study CI of turbulent velocity fluctuations at different scales. Basing on the analysis of return-time distribution of telegraphic approximation series, we propose to use the shape parameter of the Weibull distribution to measure CI. Observations of this parameter show that contrary to MI, CI tends to weaken as the scale increases. Besides, significant diurnal variations, showing that CI tends to strengthen during the daytime (under unstable conditions) and weaken during the nighttime (under stable conditions), are found at different observation heights. In the convective boundary layer, the mixed-layer similarity is found to scale the CI exponent better than the Monin–Obukhov similarity. At night, CI is found to vary less with height in the regime with large mean wind speeds than in the regime with small mean wind speeds, according to the hockey-stick theory.

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Pietrycha, Albert E., and Erik N. Rasmussen. "Finescale Surface Observations of the Dryline: A Mobile Mesonet Perspective." Weather and Forecasting 19, no. 6 (December 1, 2004): 1075–88. http://dx.doi.org/10.1175/819.1.

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Abstract Mobile mesonet line normal, time-to-space converted data analysis on three meridional drylines that occurred in west Texas on 10 June 1999 and 5 May 2000 are presented herein; two occurred in a quiescent environment on 5 May 2000. Based on the data, the mixing zone across the dryline was composed of a series of large horizontal moisture differentials that were highly variable in width, ranging from 5 km down to several hundred meters. The largest dewpoint differential sampled was 10.0°C over 185 m. Concurrent with a deceleration of dryline movement to nearly stationary, and while moisture differentials strengthened, surface-based mesoscale vertical circulations with horizontal diameters of 2 km down to less than 300 m were resolved in the data, and visual observations were made of numerous, strongly rotating dust devils. The estimated diameters of the largest dust devils were ∼80–100 m and ∼1 km deep, and these persisted for tens of minutes. All vortices were found to move along or adjacent to the zones of moisture differential. Additionally, when the circulations were observed, spatially isolated cumulus clouds located along the dryline exhibited rapid vertical development. It is plausible that the vortices protect an ascending air parcel by inhibiting mixing, thus allowing the parcel to reach its local lifting condensation level and level of free convection with relatively greater buoyancy than parcels not contained in vortices.

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Stow, C. David, Stuart G. Bradley, Keith E. Farrington, Kim N. Dirks, and Warren R. Gray. "A Rain Gauge for the Measurement of Finescale Temporal Variations." Journal of Atmospheric and Oceanic Technology 15, no. 1 (February 1998): 127–35. http://dx.doi.org/10.1175/1520-0426(1998)015<0127:argftm>2.0.co;2.

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Jameson, A. R., M. L. Larsen, and A. B. Kostinski. "Disdrometer Network Observations of Finescale Spatial–Temporal Clustering in Rain." Journal of the Atmospheric Sciences 72, no. 4 (March 31, 2015): 1648–66. http://dx.doi.org/10.1175/jas-d-14-0136.1.

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Abstract The spatial clustering of drops is a defining characteristic of rain on all scales from centimeters to kilometers. It is the physical basis for much of the observed variability in rain. The authors report here on the temporal–spatial 1-min counts using a network of 21 optical disdrometers over a small area near Charleston, South Carolina. These observations reveal significant differences between spatial and temporal structures (i.e., clustering) for different sizes of drops, which suggest that temporal observations of clustering cannot be used to infer spatial clustering simply using by an advection velocity as has been done in past studies. It is also shown that both spatial and temporal clustering play a role in rain variability depending upon the drop size. The more convective rain is dominated by spatial clustering while the opposite holds for the more stratiform rain. Like previous time series measurements by a single disdrometer but in contradiction with widely accepted drop size distribution power-law relations, it is also shown that there is a linear relation between 1-min averages of the rainfall rate R over the network and the average total number of drops Nt. However, the network (area) R–Nt relation differs from those derived strictly from time series observations by individual disdrometers. These differences imply that the temporal and spatial size distributions and their variabilities are not equivalent.

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29

Pinkel, Robert, and Steven Anderson. "Toward a Statistical Description of Finescale Strain in the Thermocline." Journal of Physical Oceanography 22, no. 7 (July 1992): 773–95. http://dx.doi.org/10.1175/1520-0485(1992)022<0773:tasdof>2.0.co;2.

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30

Chunchuzov, Igor. "Nonlinear Formation of the Three-Dimensional Spectrum of Mesoscale Wind Velocity and Temperature Fluctuations in a Stably Stratified Atmosphere." Journal of the Atmospheric Sciences 75, no. 10 (October 2018): 3447–67. http://dx.doi.org/10.1175/jas-d-17-0398.1.

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The theory of formation of the space–time spectrum of the mesoscale fluctuations in the horizontal wind velocity and vertical displacements (or relative temperature fluctuations) in a stably stratified atmosphere is developed. The nonlinear mechanism of the formation of the finescale layered inhomogeneities in the internal wave fields associated with the nonresonant wave–wave and wave–vortical mode interactions is described. The 3D spatial spectra of the layered inhomogeneities are obtained from the approximate solutions of Lagrangian motion equations for internal waves and subsequent transition to the Eulerian coordinate system. Because of such transition, the advection of internal waves by the wind induced by the waves and vortical modes is taken into account. The contributions from the large-scale wind disturbances and finescale layered inhomogeneities to the horizontal wavenumber spectrum of the velocity fluctuations are found. Using an analytic form obtained for the 3D spectrum, the comparison is made between the modeled one-dimensional (1D) wavenumber spectra (vertical and horizontal) of the fluctuations with the observed spectra in the upper troposphere and lower stratosphere. The observed 1D (horizontal and vertical) wavenumber spectra of the horizontal velocity fluctuations with a −3 power-law decay are explained.

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31

Bluestein, Howard B., Zachary B. Wienhoff, David D. Turner, Dylan W. Reif, Jeffrey C. Snyder, Kyle J. Thiem, and Jana B. Houser. "A Comparison of the Finescale Structures of a Prefrontal Wind-Shift Line and a Strong Cold Front in the Southern Plains of the United States." Monthly Weather Review 145, no. 8 (August 2017): 3307–30. http://dx.doi.org/10.1175/mwr-d-16-0403.1.

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The objectives of this study are to determine the finescale characteristics of the wind and temperature fields associated with a prefrontal wind-shift line and to contrast them with those associated with a strong cold front. Data from a mobile, polarimetric, X-band, Doppler radar and from a surveillance S-band radar, temperature profiles retrieved from a thermodynamic sounder, and surface observations from the Oklahoma Mesonet are used to analyze a prefrontal wind-shift line in Oklahoma on 11 November 2013. Data from the same mobile radar and the Oklahoma Mesonet are used to identify the finescale characteristics of the wind field associated with a strong surface cold front in Oklahoma on 9 April 2013. It is shown that the prefrontal wind-shift line has a kinematic and thermodynamic structure similar to that of an intrusion (elevated density current), while the cold front has a kinematic structure similar to that of a classic density current. Other characteristics of the prefrontal wind-shift line and front are also discussed. Evidence of waves generated at the leading edge of the prefrontal wind-shift line is presented.

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32

Kunze, Eric, and Miles A. Sundermeyer. "The Role of Intermittency in Internal-Wave Shear Dispersion." Journal of Physical Oceanography 45, no. 12 (December 2015): 2979–90. http://dx.doi.org/10.1175/jpo-d-14-0134.1.

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AbstractThis paper revisits a long-standing discrepancy between (i) 1–5-km isopycnal diffusivities of O(1) m2 s−1 based on dye spreading and (ii) inferences of O(0.1) m2 s−1 from internal-wave shear dispersion Kh ~ 〈Kz〉〈〉/f2 in several studies in the stratified ocean interior, where 〈Kz〉 is the bulk average diapycnal diffusivity, 〈〉 the finescale shear variance, and f the Coriolis frequency. It is shown that, taking into account (i) the intermittency of shear-driven turbulence, (ii) its lognormality, and (iii) its correlation with unstable finescale near-inertial shear, internal-wave shear dispersion cannot necessarily be discounted based on available information. This result depends on an infrequent occurrence of turbulence bursts, as is observed, and a correlation between diapycnal diffusivity Kz and the off-diagonal vertical strain, or the vertical gradient of horizontal displacement, |χz| = |∫Vz dt|, which is not well known and may vary from region to region. Taking these factors into account, there may be no need to invoke additional submesoscale mixing mechanisms such as vortical-mode stirring or internal-wave Stokes drift to explain the previously reported discrepancies.

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33

Tzortzis, Roxane, Andrea M. Doglioli, Monique Messié, Stéphanie Barrillon, Anne A. Petrenko, Lloyd Izard, Yuan Zhao, Francesco d'Ovidio, Franck Dumas, and Gérald Gregori. "The contrasted phytoplankton dynamics across a frontal system in the southwestern Mediterranean Sea." Biogeosciences 20, no. 16 (August 22, 2023): 3491–508. http://dx.doi.org/10.5194/bg-20-3491-2023.

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Abstract. Numerical simulations have shown that finescale structures such as fronts are often suitable places for the generation of vertical velocities, transporting subsurface nutrients to the euphotic zone and thus modulating phytoplankton abundance and community structure. In these structures, direct in situ estimations of the phytoplankton growth rates are rare; although difficult to obtain, they provide precious information on the ecosystem functioning. Here, we consider the case of a front separating two water masses characterized by several phytoplankton groups with different abundances in the southwestern Mediterranean Sea. In order to estimate possible differences in growth rates, we measured the phytoplankton diurnal cycle in these two water masses as identified by an adaptive and Lagrangian sampling strategy. A size-structured population model was then applied to these data to estimate the growth and loss rates for each phytoplankton group identified by flow cytometry, showing that these two population parameters are significantly different on the two sides of the front and consistent with the relative abundances. Our results introduce a general method for estimating growth rates at frontal systems, paving the way for in situ exploration of finescale biophysical interactions.

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34

Booher, Evan C. J., and Annika W. Walters. "Identifying Translocation Sites for a Climate Relict Population of Finescale Dace." Transactions of the American Fisheries Society 151, no. 2 (February 14, 2022): 245–59. http://dx.doi.org/10.1002/tafs.10348.

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35

Glasheen, Katherine, James Pinto, Matthias Steiner, and Eric Frew. "Assessment of Finescale Local Wind Forecasts Using Small Unmanned Aircraft Systems." Journal of Aerospace Information Systems 17, no. 4 (April 2020): 182–92. http://dx.doi.org/10.2514/1.i010747.

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36

Siebert, Holger, Harald Franke, Katrin Lehmann, Rolf Maser, Ewe Wei Saw, Dieter Schell, Raymond A. Shaw, and Manfred Wendisch. "Probing Finescale Dynamics and Microphysics of Clouds with Helicopter-Borne Measurements." Bulletin of the American Meteorological Society 87, no. 12 (December 2006): 1727–38. http://dx.doi.org/10.1175/bams-87-12-1727.

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37

George, Ron, and John L. Largier. "Description and Performance of Finescale Drifters for Coastal and Estuarine Studies." Journal of Atmospheric and Oceanic Technology 13, no. 6 (December 1996): 1322–26. http://dx.doi.org/10.1175/1520-0426(1996)013<1322:dapofd>2.0.co;2.

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38

Atkins, Nolan T., Roger M. Wakimoto, and Conrad L. Ziegler. "Observations of the Finescale Structure of a Dryline during VORTEX 95." Monthly Weather Review 126, no. 3 (March 1998): 525–50. http://dx.doi.org/10.1175/1520-0493(1998)126<0525:ootfso>2.0.co;2.

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39

Wurman, Joshua, and Swarndeep Gill. "Finescale Radar Observations of the Dimmitt, Texas (2 June 1995), Tornado." Monthly Weather Review 128, no. 7 (July 2000): 2135–64. http://dx.doi.org/10.1175/1520-0493(2000)128<2135:frootd>2.0.co;2.

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40

Polzin, K. L., E. Kunze, J. M. Toole, and R. W. Schmitt. "The Partition of Finescale Energy into Internal Waves and Subinertial Motions." Journal of Physical Oceanography 33, no. 1 (January 2003): 234–48. http://dx.doi.org/10.1175/1520-0485(2003)033<0234:tpofei>2.0.co;2.

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41

Sutor, M. M., T. J. Cowles, W. T. Peterson, and S. D. Pierce. "Acoustic observations of finescale zooplankton distributions in the Oregon upwelling region." Deep Sea Research Part II: Topical Studies in Oceanography 52, no. 1-2 (January 2005): 109–21. http://dx.doi.org/10.1016/j.dsr2.2004.09.029.

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42

Häfliger, Vincent, Eric Martin, Aaron Boone, Florence Habets, Cédric H. David, Pierre-A. Garambois, Hélène Roux, et al. "Evaluation of Regional-Scale River Depth Simulations Using Various Routing Schemes within a Hydrometeorological Modeling Framework for the Preparation of the SWOT Mission." Journal of Hydrometeorology 16, no. 4 (July 29, 2015): 1821–42. http://dx.doi.org/10.1175/jhm-d-14-0107.1.

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Abstract The Surface Water and Ocean Topography (SWOT) mission will provide free water surface elevations, slopes, and river widths for rivers wider than 50 m. Models must be prepared to use this new finescale information by explicitly simulating the link between runoff and the river channel hydraulics. This study assesses one regional hydrometeorological model’s ability to simulate river depths. The Garonne catchment in southwestern France (56 000 km2) has been chosen for the availability of operational gauges in the river network and finescale hydraulic models over two reaches of the river. Several routing schemes, ranging from the simple Muskingum method to time-variable parameter kinematic and diffusive waves schemes, are tested. The results show that the variable flow velocity schemes are advantageous for discharge computations when compared to the original Muskingum routing method. Additionally, comparisons between river depth computations and in situ observations in the downstream Garonne River led to root-mean-square errors of 50–60 cm in the improved Muskingum method and 40–50 cm in the kinematic–diffusive wave method. The results also highlight SWOT’s potential to improve the characterization of hydrological processes for subbasins larger than 10 000 km2, the importance of an accurate digital elevation model, and the need for spatially varying hydraulic parameters.

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43

Liang, Chang-Rong, Xiao-Dong Shang, Yong-Feng Qi, Gui-Ying Chen, and Ling-Hui Yu. "A Modified Finescale Parameterization for Turbulent Mixing in the Western Equatorial Pacific." Journal of Physical Oceanography 51, no. 4 (April 2021): 1133–43. http://dx.doi.org/10.1175/jpo-d-20-0205.1.

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AbstractFinescale parameterizations are of great importance to explore the turbulent mixing in the open ocean due to the difficulty of microstructure measurements. Studies based on finescale parameterizations have greatly aided our knowledge of the turbulent mixing in the open ocean. In this study, we introduce a modified finescale parameterization (MMG) based on shear/strain variance ratio Rω and compare it with three existing parameterizations, namely, the MacKinnon–Gregg (MG) parameterization, the Gregg–Henyey–Polzin (GHP) parameterization based on shear and strain variances, and the GHP parameterization based on strain variance. The result indicates that the prediction of MG parameterization is the best, followed by the MMG parameterization, then the shear-and-strain-based GHP parameterization, and finally the strain-based GHP parameterization. The strain-based GHP parameterization is less effective than the shear-and-strain-based GHP parameterization, which is mainly due to its excessive dependence on stratification. The predictions of the strain-based MMG parameterization can be comparable to that of the MG parameterization and better than that of the shear-and-strain-based GHP parameterization. Most importantly, MMG parameterization is even effective over rough topography where the GHP parameterization fails. This modified MMG parameterization with prescribed Rω can be applied to extensive CTD data. It would be a useful tool for researchers to explore the turbulent mixing in the open ocean.

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44

Campbell, Leah S., and W. James Steenburgh. "Finescale Orographic Precipitation Variability and Gap-Filling Radar Potential in Little Cottonwood Canyon, Utah." Weather and Forecasting 29, no. 4 (July 22, 2014): 912–35. http://dx.doi.org/10.1175/waf-d-13-00129.1.

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Abstract Finescale variations in orographic precipitation pose a major challenge for weather prediction, winter road maintenance, and avalanche forecasting and mitigation in mountainous regions. In this investigation, ground-based X-band radar observations collected during intensive observing period 6 (IOP6) of the Storm Chasing Utah Style Study (SCHUSS) are used to provide an example of these variations during a winter storm in the Wasatch Mountains of northern Utah. Emphasis is placed on precipitation features in and around Little Cottonwood Canyon (LCC), which cuts orthogonally eastward into the central Wasatch Mountains. Precipitation during the weakly stratified prefrontal storm stage featured a wavelike barrier-scale reflectivity maximum over the Wasatch Crest and upper LCC that extended weakly westward along the transverse ridges flanking LCC. This precipitation pattern appeared to reflect a veering wind profile, with southwesterly flow over the transverse ridges but cross-barrier westerly flow farther aloft. Sublimation within dry subcloud air further diminished low-level radar reflectivities over lower LCC. In contrast, the cold-frontal stage was associated with stronger reflectivities over lower LCC and the adjoining north- to northwest-facing canyon wall, consistent with shallow, northwesterly upslope flow. These results highlight the finescale precipitation variations that can occur during winter storms in complex terrain and demonstrate the potential for improved analysis and forecasting of precipitation in LCC using a gap-filling radar.

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45

Waterman, Stephanie, Kurt L. Polzin, Alberto C. Naveira Garabato, Katy L. Sheen, and Alexander Forryan. "Suppression of Internal Wave Breaking in the Antarctic Circumpolar Current near Topography." Journal of Physical Oceanography 44, no. 5 (April 24, 2014): 1466–92. http://dx.doi.org/10.1175/jpo-d-12-0154.1.

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Abstract Simultaneous full-depth microstructure measurements of turbulence and finestructure measurements of velocity and density are analyzed to investigate the relationship between turbulence and the internal wave field in the Antarctic Circumpolar Current. These data reveal a systematic near-bottom overprediction of the turbulent kinetic energy dissipation rate by finescale parameterization methods in select locations. Sites of near-bottom overprediction are typically characterized by large near-bottom flow speeds and elevated topographic roughness. Further, lower-than-average shear-to-strain ratios indicative of a less near-inertial wave field, rotary spectra suggesting a predominance of upward internal wave energy propagation, and enhanced narrowband variance at vertical wavelengths on the order of 100 m are found at these locations. Finally, finescale overprediction is typically associated with elevated Froude numbers based on the near-bottom shear of the background flow, and a background flow with a systematic backing tendency. Agreement of microstructure- and finestructure-based estimates within the expected uncertainty of the parameterization away from these special sites, the reproducibility of the overprediction signal across various parameterization implementations, and an absence of indications of atypical instrument noise at sites of parameterization overprediction, all suggest that physics not encapsulated by the parameterization play a role in the fate of bottom-generated waves at these locations. Several plausible underpinning mechanisms based on the limited available evidence are discussed that offer guidance for future studies.

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46

Hirose, Masafumi, Riko Oki, Shuji Shimizu, Misako Kachi, and Tomohiko Higashiuwatoko. "Finescale Diurnal Rainfall Statistics Refined from Eight Years of TRMM PR Data." Journal of Applied Meteorology and Climatology 47, no. 2 (February 1, 2008): 544–61. http://dx.doi.org/10.1175/2007jamc1559.1.

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Abstract The adequacy of hourly rainfall sampling was examined in terms of the detection of diurnal variations using 8 yr (1998–2005) of data observed by the precipitation radar on the Tropical Rainfall Measuring Mission (TRMM) satellite. It was found that the monthly and hourly rain samples for each 0.2° grid point over the 8-yr period are composed of multiple precipitation systems. In this study, a “3-h-significant diurnal peak” was defined as the time of maximum rainfall with consecutive positive anomalies for more than 3 h. The fraction of the analyzed area with a 3-h-significant diurnal peak increased annually and accounted for 43% of the total global tropics at 0.2° resolution over the 8-yr period. The diurnal signature over Tibet and the Amazon showed a high degree of spatial uniformity (at >10° scale). The degree of similarity and locations of the regional diurnal characteristics are described in terms of seasonal variations and at multiple resolutions based on spatial uniformity. For example, uniform early-afternoon peaks generally appear over the coastal land and areas of high relief, whereas a seasonally invariant early-afternoon peak over the low-lying Amazon basin is recognized as a regional characteristic. In areas of coastal ocean, early-morning peaks appear in certain regions such as the area surrounding the so-called Maritime Continent and the area off the west coast of Mexico. These peaks are distinct from the global characteristics of late-morning rainfall maxima recorded over most coastal oceans and early-morning peaks recorded over open ocean. The results are also compared with those derived from TRMM Microwave Imager (TMI) data. In addition to obtaining a coherent signal, regional differences in the timing of maximum rainfall over the Tibetan Plateau were addressed; this discrepancy is attributed to limitations of the scattering algorithm used for TMI data in terms of detecting shallow convection and screening cold surfaces.

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47

Miao, Qun, and Bart Geerts. "Finescale Vertical Structure and Dynamics of Some Dryline Boundaries Observed in IHOP." Monthly Weather Review 135, no. 12 (December 1, 2007): 4161–84. http://dx.doi.org/10.1175/2007mwr1982.1.

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Abstract Several radar fine lines, all with a humidity contrast, were sampled in the central Great Plains during the 2002 International H2O Project (IHOP). This study primarily uses aircraft and airborne millimeter-wave radar observations to dynamically interpret the presence and vertical structure of these fine lines as they formed within the well-developed convective boundary layer. In all cases the fine line represents a boundary layer convergence zone. This convergence sustains a sharp contrast in humidity, and usually in potential temperature, across the fine line. The key question addressed herein is whether, at the scale examined here (∼10 km), the airmass contrast itself, in particular the horizontal density (virtual potential temperature) difference and resulting solenoidal circulation, is responsible for the sustained convergence and the radar fine line. For the 10 cases examined herein, the answer is affirmative.

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48

Lensky, Itamar M., and Uri Dayan. "Detection of Finescale Climatic Features from Satellites and Implications for Agricultural Planning." Bulletin of the American Meteorological Society 92, no. 9 (September 1, 2011): 1131–36. http://dx.doi.org/10.1175/2011bams3160.1.

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49

Weiss, Christopher C., Howard B. Bluestein, Andrew L. Pazmany, and Bart Geerts. "Finescale Radar Observations of a Dryline during the International H2O Project (IHOP_2002)." Meteorological Monographs 55 (November 1, 2008): 203–28. http://dx.doi.org/10.1175/0065-9401-33.55.203.

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Abstract A case study of a double dryline on 22 May 2002 is presented. Mobile, 3-mm-wavelength Doppler radars from the University of Massachusetts and the University of Wyoming (Wyoming cloud radar) were used to collect very fine resolution vertical-velocity data in the vicinity of each of the moisture gradients associated with the drylines. Very narrow (50–100 m wide) channels of strong upward vertical velocity (up to 8 m s–1) were measured in the convergence zone of the easternmost dryline, larger in magnitude than reported with previous drylines. Distinct areas of descending motion were evident to the east and west of both drylines. Radar data are interpreted in the context of other observational platforms available during the International H2O Project (IHOP-2002). a variational ground-based mobile radar data processing technique was developed and applied to pseudo-dual-Doppler data collected during a rolling range-height indicator deployment. It was found that there was a secondary (vertical) circulation normal to the easternmost moisture gradient; the circulation comprised an easterly component near-surface flow to the east, a strong upward vertical component in the convergence zone, a westerly return, flow above the convective boundary layer, and numerous regions of descending motion, the most prominent approximately 3–5 km to the east of the surface convergence zone.

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50

Polzin, Kurt. "Idealized Solutions for the Energy Balance of the Finescale Internal Wave Field*." Journal of Physical Oceanography 34, no. 1 (January 2004): 231–46. http://dx.doi.org/10.1175/1520-0485(2004)034<0231:isfteb>2.0.co;2.

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Journal articles on the topic 'Finescale'

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