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NASA NTRS2023

Mesoscale Phenomena and Their Contribution to the Global Response: A Focus on the Magnetotail Transition Region and Magnetosphere-Ionosphere Coupling

An important question that is being increasingly studied across subdisciplines of Heliophysics is “how do mesoscale phenomena contribute to the global response of the system?” This review paper focuses on this question within two specific but interlinked regions in Near-Earth space: the magnetotail’s transition region to the inner magnetosphere and the ionosphere. There is a concerted effort within the Geospace Environment Modeling (GEM) community to understand the degree to which mesoscale transport in the magnetotail contributes to the global dynamics of magnetic flux transport and dipolarization, particle transport and injections contributing to the storm-time ring current development, and the substorm current wedge. Because the magnetosphere-ionosphere is a tightly coupled system, it is also important to understand how mesoscale transport in the magnetotail impacts auroral precipitation and the global ionospheric system response. Groups within the Coupling, Energetics and Dynamics of Atmospheric Regions Program (CEDAR) community have also been studying how the ionosphere-thermosphere responds to these mesoscale drivers. These specific open questions are part of a larger need to better characterize and quantify mesoscale “messengers” or “conduits” of information—magnetic flux, particle flux, current, and energy—which are key to understanding the global system. After reviewing recent progress and open questions, we suggest datasets that, if developed in the future, will help answer these questions.

transition region↗

NASA NTRS1989

Planned ER-2 Doppler radar (EDOP) for studying convective storms and mesoscale phenomena

A radar development is presently funded by the NASA Mesoscale Atmospheric Research Program to build an X-band Doppler radar (EDOP) for the ER-2 aircraft for measuring the structure of updrafts and downdrafts in deep convective systems. In this paper, the radar's scientific objectives and characteristics are briefly reviewed. These objectives include documentation of deep isolated thunderstorms, examination of cloud top and anvil structure, structure of microscale convective systems, cloud microphysics, and testing of satellite precipitation estimation algorithms. System specifications for the radar are given.

Heymsfield, Gerald M.↗

NASA NTRS1990

HIS analyses of mesoscale phenomena

Results are presented from two sets of measurements made by the High-resolution Interferometer Sounder (HIS) during two aircraft flights over the Cooperative-Huntsville-Meteorological-Experiment region on June 15 and 19, 1986. It is shown that the temperature and the dew-point field retrieved from HIS spectra contain distinct mesoscale structures. The features in the HIS dew-point fields agreed well with the cloud and moisture structures observed in visible and 6.7 micron GOES imagery.

Bradshaw, John T.↗

NASA NTRS1975

The study of mesoscale phenomena, winter monsoon clouds and snow area

The author has identified the following significant results. The clouds under a moderate winter monsoon situation taken with S190A camera reveal existence of clouds with band structure of various wavelengths. The wavelength ranges from 0.4 to 3.5 kms. There was a good relationship between the longitudinal cloud band and vertical wind shear. There was a distinct difference in size of clouds between the Japan Sea side or upwind side and the Pacific Ocean side or downwind side of the Japanese mainland. Large solid cumulus clusters have the size of 20 x 35 sq km over the Japan Sea off the coast of Hokuriku District. It was found that S190A aerial color pictures showing shadows of fair weather cumuli over the sea could be successfully used in estimating cloud height while S190A station 1 picture was more useful over the land since it could more clearly distinguish shadow from vegetation. The height of fair weather cumuli estimated from shadows agree with the lifted condensation level. It was also found that these pictures were effectively used in delineating snow cover area. S192 data, especially IR channel, were found to be effective in finding topography of nimbostratus.

Tsuchiya, K.↗

NASA NTRS1976

Study of mesoscale phenomena, winter monsoon clouds and snow area based on LANDSAT data

The author has identified the following significant results. Most longitudinal clouds which appear as continuous linear clouds are composed of small transversal clouds. There are mountain waves of different wavelength in a comparatively narrow area indicating complicated orographical effects on wind and temperature distribution or on both dynamical and static stability condition. There is a particular shape of cirrus cloud suggestive of turbulence in the vicinity of CAT in the upper troposphere near jet stream level and its cold air side. Thin cirrus of overcast condition can be distinguished by MSS; however, extremely thin cirrus of partly cloudy condition cannot be detected even in LANDSAT data. This presents a serious problem in the interpretation of satellite thermal infrared radiation data since they affect the value.

Tsuchiya, K.↗

NASA NTRS1983

Techniques for diagnosing mesoscale phenomena affecting aviation using VAS satellite data

A major advance in geostationary satellite observations occurred recently with the inclusion of an experimental instrument aboard the latest Geostationary Operational Environmental Satellites (GOES). This instrument, called the Visible Infrared Spin-Scan Radiometer (VISSR) Atmospheric Sounder (VAS), permits simultaneous observations of the atmosphere in up to 12 infrared channels, in addition to the visible image. In the present investigation, particular emphasis is placed on the ability of VAS imagery and derived soundings to delineate isolated, meso-scale regions of convective instability. The results of the investigation point to the ability of the VAS instrument to delineate meteorologically meaningful patterns of low-level moisture and mid-level dryness and to the utility of the image overlay procedure for isolating, in real time, regions of convective potential, at time and space scales unresolvable using radiosonde data alone.

Petersen, R. A.↗

NASA NTRS1982

Investigation of mesoscale meteorological phenomena as observed by geostationary satellite

Satellite imagery plus conventional synoptic observations were used to examine three mesoscale systems recently observed by the GOES-EAST satellite. The three systems are an arc cloud complex (ACC), mountain lee wave clouds and cloud streets parallel to the wind shear. Possible gravity-wave activity is apparent in all three cases. Of particular interest is the ACC because of its ability to interact with other mesoscale phenomena to produce or enhance convection.

Brundidge, K. C.↗

NASA NTRS1979

Observing, analyzing, and modeling mesoscale weather phenomena

The objective of the paper is to place current research into mesoscale weather phenomena in proper perspective, and to discuss key problems to be addressed in the coming years. Key observing systems and field programs are examined, along with analysis techniques in context of the dynamic models with which they interact. The discussion covers different classes of dynamic models, including prediction models, simulation models, and parameterization schemes.

Kreitzberg, C. W.↗

NASA NTRS1977

Mesoscale cloud phenomena observed by LANDSAT

Examples of certain mesoscale cloud features - jet cirrus, eddies/vortices, cloud banding, and wave clouds - were collected from LANDSAT imagery and placed into Mason's four groups of causes of cloud formation based on the mechanism of vertical motion which produces condensation. These groups are as follows: (1) layer clouds formed by widespread regular ascent; (2) layer clouds caused by irregular stirring motions; (3) convective clouds; and (4) clouds formed by orographic disturbances. These mechanisms explain general cloud formation. Once formed, other forces may play a role in the deformation of a cloud or cloud mass into unusual and unique meso- and microscale patterns. Each example presented is followed by a brief discussion describing the synoptic situation, and some inference into the formation and occurrence of the more salient features. No major attempt was made to discuss in detail the meteorological and topographic interplay producing these mesoscale features.

Ormsby, J. P.↗

NASA NTRS1996

(abstract) Detection of Mesoscale Oceanic Phenomena in the Southern California Bight via ERS-1 SAR

ERS-1 SAR images are examined with the intent of identifying mesoscale oceanic phenomena in the Southern California Bight (SCB). The SCB is a region of dynamic physical and biological processes, and as such has long been studied. The ERS-1 SAR images are augmented with other remote sensing data, including SIR-C SAR, AVHRR, ERS-1 ATSR, and Space Shuttle hand-held photography. Analysis of these images has revealed a more dynamic mesoscale field than was previously suspected. Eddies with scales on the order of 20-30 km in diameter have been the most common mesoscale features evident, but the presence of oceanic fronts and internal waves, as well as atmospheric internal waves, have been documented as well. The multisensor data record will provide insight as to the underlying ocean and meterological conditions that lead to the prevalence especially of the eddies in this region.

Southern California Bight SCB remote sensing data ↗

NASA NTRS1985

Use of observational and model-derived fields and regime model output statistics in mesoscale forecasting

Various empirical and statistical weather-forecasting studies which utilize stratification by weather regime are described. Objective classification was used to determine weather regime in some studies. In other cases the weather pattern was determined on the basis of a parameter representing the physical and dynamical processes relevant to the anticipated mesoscale phenomena, such as low level moisture convergence and convective precipitation, or the Froude number and the occurrence of cold-air damming. For mesoscale phenomena already in existence, new forecasting techniques were developed. The use of cloud models in operational forecasting is discussed. Models to calculate the spatial scales of forcings and resultant response for mesoscale systems are presented. The use of these models to represent the climatologically most prevalent systems, and to perform case-by-case simulations is reviewed. Operational implementation of mesoscale data into weather forecasts, using both actual simulation output and method-output statistics is discussed.

Forbes, G. S.↗

NASA NTRS2006

Using a Network of Boundary Layer Profilers to Characterize the Atmosphere at a Major Spaceport

Space launch, landing, and ground operations at the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) in east-central Florida are highly sensitive to mesoscale weather conditions throughout the year. Due to the complex land-water interfaces and the important role of mesoscale circulations, a high-resolution network of five 915-MHz Doppler Radar Wind Profilers (DRWP) and 44 wind towers was installed over the KSC/CCAFS area. By using quality-controlled 915-MHz DRAT data along with the near-surface tower observations, the Applied Meteorology Unit and KSC Weather Office have studied the development and evolution of various mesoscale phenomena across KSC/CCAFS such as sea and land breezes, low-level jets, and frontal passages. This paper will present some examples of mesoscale phenomena that can impact space operations at KSC/CCAFS, focusing on the utility of the 915-MHz DRWP network in identifying important characteristics of sea/land breezes and low-level jets.

Case, Jonathan L.↗

NASA NTRS1984

Radar analyses of mesoscale meteorological phenomena during the AVE/VAS correlation field experiment

Radar data were collected during the selected critical times of the field experiment and subsequently analyzed for specific items. The analyses of the radar data for the AVE/VAS experiment provided statistically significant values for each of the 10 Km by 10 Km grids within radar range. The resulting information for correlation with satellite data included the following derived items that were averaged for each grid area: (1) rainfall rate in mm/hr; (2) dBZ (reflectivity) values; (3) accumulated rainfall values per hour; (4) accumulated rainfall values for a 6-hour period; (5) vertically integrated liquid water content per square meter; and (6) vertical height of the radar axis at the midpoint of each grid. Additional products derived from radar data are being investigated. An example of one such product is the derivation of the errors in integrated rainfall with different sampling periods. This is of significance for correlation with satellite data in that normally a step-function type of rainfall rate is used to derive the total rainfall over a period.

Huebner, G. L.↗

NASA NTRS1992

Meso-beta scale numerical simulation studies of terrain-induced jet streak mass/momentum perturbations

Work performed during the report period is summarized. The first numerical experiment which was performed on the North Carolina Supercomputer Center's CRAY-YMP machine during the second half of FY92 involved a 36 hour simulation of the CCOPE case study. This first coarse-mesh simulation employed the GMASS model with a 178 x 108 x 32 matrix of grid points spaced approximately 24 km apart. The initial data was comprised of the global 2.5 x 2.5 degree analyses as well as all available North American rawinsonde data valid at 0000 UTC 11 July 1981. Highly-smoothed LFM-derived terrain data were utilized so as to determine the mesoscale response of the three-dimensional atmosphere to weak terrain forcing prior to including the observed highly complex terrain of the northern Rocky Mountain region. It was felt that the model should be run with a spectrum of terrain geometries, ranging from observed complex terrain to no terrain at all, to determine how crucial the terrain was in forcing the mesoscale phenomena. Both convection and stratiform (stable) precipitation were not allowed in this simulation so that their relative importance could be determined by inclusion in forth-coming simulations. A full suite of planetary boundary layer forcing was allowed in the simulation, including surface sensible and latent heat fluxes employing the Blakadar PBL formulation. The details of this simulation, which in many ways could be considered the control simulation, including the important synoptic-scale, meso-alpha scale, and meso-beta scale circulations is described. These results are compared to the observations diagnosed by Koch and his colleagues as well as hypotheses set forth in the project proposal for terrain-influences upon the jet stream and their role in the generation of mesoscale wave phenomenon. The fundamental goal of the analyses being the discrimination among background geostrophic adjustment, terrain influences, and shearing instability in the initiation and maintainance of mesoscale internal wave phenomena. Based upon these findings, FY93 plans are discussed. A review of linear theory and theoretical modeling of a geostrophic zonal wind anomaly is included.

Lin, Yuh-Lang↗

NASA NTRS1983

AVE/VAS experiment: Synoptic summary and preliminary results

The AVE/VAS ground truth field experiment was conducted during the Spring of 1982 severe storms and weather research program. The experiment consisted of acquiring correlative ground truth measurements of rawinsonde data, corresponding to the time and space resolutions of VAS sounding data. The objectives of the AVE/VAS experiment are: (1) to acquire four dimensional data sets of the actual atmospheric structure down to the mesoscale; (2) to provide measurements for quantitative comparisons between ground based and VAS-derived atmospheric parameters; (3) to evaluate the impact of VAS data on diagnostic analysis of structural features and dynamical processes important to the development of mesoscale phenomena; (4) to evaluate the impact of VAS data on numerical model simulations, nowcasting, and other mesoscale forecasting systems.

Jedlovec, G. J.↗

NASA NTRS1987

Regional models - Emerging research tools for synoptic meteorologists

A number of regional-scale numerical weather prediction models are discussed together with their application to the study of the structure and the dynamics of mesoscale phenomena. Consideration is given to investigations of natural phenomena (such as midlatitude cyclones and related baroclinic disturbances; upper-level jet-front systems; surface frontal zones, squall lines, and rain bands; mesoscale convective systems; and severe-storm environments) in which two operational models and four research models are used for regional-model studies. It is shown that these models provide investigators with four-dimensional dynamically consistent data sets to supplement and extend those available from observations.

Keyser, Daniel↗

NASA NTRS1981

Oceanic eddy variability measured by GEOS 3 altimeter crossover differences

Eddy statistics of sea height variations associated with dynamic ocean currents, gathered by GEOS 3 altimetry (25 cm), are discussed. Time variable flow is noted to be measureable using altimeter height and orbit information by means of three techniques: collinear tracks, where rms variability can be determined for mesoscale phenomena measured along parallel tracks; mean surfaces, using a 3-dimensional mapping of the sea surface for an accurate representation of the surface undulations; and crossover differences, such as between data tracks from GEOS and Seasat which have reduced ephemeris error over scales of a few thousand km. Mesoscale energetics have been found suitable for tracing meandering ocean currents by the crossover method. Possible sources of error are considered, including altimeter noise, orbit error, short wavelength continental shelf tides, etc., and it is determined that observations of mesoscale sea height appear to be limited only by uncertainties in the altimetry, which for Seasat was 5 cm over 60% of the world's oceans.

Cheney, R. E.↗

NASA NTRS1989

A study of turbulence near thunderstorm tops

It has been known for many years that turbulence significant for aviation often occurs near thunderstorm tops. However, that turbulence is not well-predicted because of an incomplete understanding of the processes which generate it and because of inadequate observations. The current study seeks to alleviate these problems via: (1) a comprehensive review of recent theoretical and experimental studies related to turbulence near thunderstorm tops (TNTT), and (2) three case studies designed to examine the feasibility of using data derived from commercial aircraft to study TNTT. The literature review revealed extensive evidence which showed that convection often produces significant barrier effects; several mesoscale phenomena capable of producing turbulence may occur, depending on wind and stability conditions near the thunderstorm tops. These include two- and three-dimensional lee waves, rotors, Kelvin-Helmholtz instabilities, and Karman vortices. Conventional meteorological data were combined with data derived from the aircraft flight tapes to produce quantitative descriptions of the turbulence and its mesoscale environment for the three cases.

Pantley, Kim Christine↗