| Ensemble Data Assimilation and Predictability of Tropical Cyclones |
30 Sep 2009 |
7 pages |
| Authors:
Fuqing Zhang; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
 | The ultimate goals is to improve tropical cyclone track and intensity prediction through further development of the regional-scale, cloud-resolving ensemble-based data assimilation and prediction system capable of efficiently assimilating in-situ and remotely sensed observations. |
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| Cloud-Resolving Hurricane Initialization and Prediction through Assimilation of Doppler Radar Observations with an Ensemble Kalman Filter |
Jul 2009 |
23 pages |
| Authors:
Fuqing Zhang; Yonghui Weng; Jason A Sippel; Zhiyong Meng; Craig H Bishop; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| This study explores the assimilation of Doppler radar radial velocity observations for cloud-resolving hurricane analysis, initialization, and prediction with an ensemble Kalman filter (EnKF). The case studied is Hurricane Humberto (2007), the first landfalling hurricane in the United States since the end of the 2005 hurricane season and the most rapidly intensifying near-landfall storm in U.S. history. The storm caused extensive damage along the southeast Texas coast but was poorly ... |
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| Ensemble Forecasting with the Ensemble Transform Kalman Filter |
AUG 2004 |
84 pages |
| Authors:
Xugueng Wang; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| The ensemble transform Kalman filter (ETKF) initial ensemble perturbation generation scheme is introduced and compared with the simple and masked breeding schemes. Instead of directly multiplying each forecast perturbation with a rescaling factor to generate the initial perturbations as in the breeding schemes, the ETKF generates initial perturbations by postmultiplying the forecast perturbations by a transformation matrix. This matrix is chosen to ensure that the ensemble-based analysis error convariance matrix ... |
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| Wind Direction Estimates from Synthetic Aperture Radar Imagery of the Sea Surface |
2004 |
6 pages |
| Authors:
George S. Young; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| The SAR-signatures of synoptic-scale cold fronts, warm fronts, occluded fronts, and secluded fronts, including their mesoscale and microscale sub-structures have been documented. The basis for these findings is the analysis of some 6000 RADARSAT-1 SAR images from the Gulf of Alaska and from off the east coast of North America. This analysis yielded 158 cases of well defined frontal signatures: 22 warm fronts, 37 cold fronts, 3 stationary fronts, 32 ... |
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| Measurement, Analysis and Prediction of Atmospheric Boundary Layer Turbulence |
25 SEP 1998 |
15 pages |
| Authors:
J. C. Wyngaard; J. G. Brasseur; D. W. Thomson; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| The program objective was to study turbulence in the atmospheric boundary layer and to improve our ability to represent that turbulence through simple models useful in applications. Toward that end we carried out observational studies at our Rock Springs field site and theoretical and computational studies using direct and large eddy simulation. Over the duration of the project we published 22 papers on the topic in scientific journals, have four ... |
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| Warm Season Statistical Verification of the Pennsylvania State University Real Time Mesoscale Model Version 5 |
MAY 1998 |
61 pages |
| Authors:
Mark P. Fitzgerald; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| For this study, warm-season simulations from the real-time Pennsylvania State University/National Center for Atmospheric Research (PSU/ NCAR) mesoscale model, known widely as MM5, are verified against surface METAR and upper-air soundings. Verification statistics are calculated on two model domains. The 36-km coarse-mesh domain encompasses the CONUS and portions of the surrounding regions. The 12-km fine-mesh domain is centered over Pennsylvania and encompasses the surrounding states. Variables that are verified include ... |
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| Using Correlation Equations for Localization |
Jan 1998 |
3 pages |
| Authors:
John L Spiesberger; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| The long-term goal of this research is to utilize time-domain information in auto-correlation and cross-correlation functions to locate sources in multipath environments. It is assumed that the bandwidths of the sources are sufficient to resolve some multipath at the receiver(s). The technique may be especially useful in cases in which it is difficult to generate a reliable model for the propagation of sound. The specific objective of this project is ... |
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| Boundary Layer Coherent Structures (MBL ARI) |
1998 |
6 pages |
| Authors:
Hampton N. Shirer; George S. Young; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| It is well known that a substantial portion of the air/sea fluxes of heat, moisture, and momentum is accomplished via intermittent processes (Khalsa and Greenhut 1985), processes that are poorly understood at the present time. Recently, Mahrt (1989) and Sikora and Young (1993) have demonstrated that coherent structures in the marine boundary layer (MBL) are responsible for this flux intermittency. These coherent structure types include ... |
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| Tropical Cyclone Intensity Change: Simulation and Analysis |
23 SEP 97 |
9 pages |
| Authors:
Jenni L. Evans; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| The Penn State/NCAR non-hydrostatic mesoscale model (MM5) has been used to simulate idealized tropical cyclone-environment interactions successfully. To reach this stage, substantial model enhancements and additions were required. Early results have been reported to the community, with much positive feedback. Presently, further exciting results are being obtained and processed. Through the course of this grant, the observational component of this research took four separate paths. These paths are briefly described. ... |
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| Boundary Layer Coherent Structures (MBL ARI) |
97 |
8 pages |
| Authors:
Hampton N. Shirer; George S. Young; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| It is well known that a substantial portion of the air/sea fluxes of heat, moisture, and momentum is accomplished via intermittent processes, processes that are poorly understood at the present time. Recently, it has been demonstrated that coherent structures in the marine boundary layer (MBL) are responsible for this flux intermittency. These coherent structure types include such secondary circulations as two-dimensional rolls (cloud streets), three- dimensional convective cells (thermals), and ... |
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| Boundary Layer Coherent Structures, AASERT Supplement |
31 MAY 96 |
8 pages |
| Authors:
Hampton N. Shirer; George S. Young; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| It is apparent that a substantial portion of the air/sea fluxes of heat, moisture, and momentum is accomplished via intermittent processes (Khalsa and Greenhut 1985), processes that are rather poorly understood. Recently, Mahrt (1989) and Sikora and Young (1993) demonstrated that coherent structures in the marine boundary layer (MBL) are responsible for this flux-carrying intermittency. These coherent structure types include such secondary circulations as two-dimensional rolls (cloud streets), three-dimensional convective ... |
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| Boundary Layer Coherent Structures (MBL ARI) and AASERT Supplement |
JAN 95 |
13 pages |
| Authors:
Hampton N. Shirer; George S. Young; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
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| Development and Testing of Improved Techniques for Modeling the Hydrologic Cycle in a Mesoscale Weather Prediction System |
DEC 94 |
26 pages |
| Authors:
Toby N. Carlson; Thomas T. Warner; J. M. Fritsch; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| This project addresses the need to improve the surface hydrology component in mesoscale atmospheric prediction models and specifically the temperature and humidity forecasts. One way we did this was to initialize the mesoscale model with continuously updated and reasonable values of soil moisture content. To accomplish this task two approaches were taken one in which a soil hydrology model (SHM): Capehart and Carlson, 1994a) was used to update the initial ... |
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| The Vertical Distribution of Heating in the Tropical Atmosphere |
30 SEP 94 |
5 pages |
| Authors:
William M. Frank; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| This grant supported research is in two areas. The primary goal of the work was to plan and participate in the TOGA-COARE (Tropical Ocean-Global Atmosphere Couple Ocean-Atmosphere Experiment) program to analyze large-scale heat and moisture budgets with the data from that experiment. The second major goal was to analyze relationships between large-scale tropical circulations and tropical cyclone intensity changes in the Northwest Pacific. Research has gone very well in both ... |
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| Marine Boundary Layer Intermittency |
94 |
5 pages |
| Authors:
John C. Wyngaard; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| The authors created a version of Chin-Hoh Moeng's NCAR LES code that is more memory efficient, hence allowing us to run larger simulations. We simulated nearly neutral marine boundary layers having a horizontal domain size of 15 km on a side, and an inversion height of 500 m. The runs used about 400 hours of Cray supercomputer time. The LES code was also run on a smaller, 3 km horizontal ... |
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| Boundary Layer Cloud Studies in Support of ASTEX |
94 |
5 pages |
| Authors:
Bruce A. Albrecht; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
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| SAR-Related Stress Variability in the Marine Atmospheric Boundary Layer (MABL) |
94 |
12 pages |
| Authors:
Hampton N. Shirer; George S. Young; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
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| Development and Testing of Improved Techniques for Modeling the Hydrologic Cycle in a Mesoscale Weather Prediction System |
14 DEC 93 |
16 pages |
| Authors:
Thomas T. Warner; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| This research addresses the problem of moisture and temperature initializations in regional scale meteorological prediction models. Specifically, two approaches are used: one involving radar data and the second involving improved soil moisture content information. The model is initialized with rawinsonde data and then is forced to match convective signatures identified from WSR-57 radar data. Data from NOAA AVHRR radiometer data is used to initialize soil moisture information and generate large ... |
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| SAR-Related Stress Variability in the Marine Atmospheric Boundary Layer (MABL) |
30 SEP 93 |
9 pages |
| Authors:
Hampton N. Shirer; George S. Young; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| By variably stressing the sea surface, secondary circulations within the marine atmospheric boundary layer (MABL) can modulate the sea-surface wave field and so can produce discernible signatures on SAR images of the ocean. Indeed, at the Fall '93 ARI workshop, Robert Beal showed ERS-I images illustrating the ubiquity of these signatures during the second HIGH-RES cruise in June 1993. Among the resulting signatures, the quasi-linear and cellular microscale patterns still ... |
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| Fluid-Modeling Studies of Convective Dispersion Processes |
30 SEP 1993 |
20 pages |
| Authors:
J. C. Wyngaard; Mark Piper; W. H. Snyder; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| These experiments are part of a project whose objectives are to improve our understanding of diffusion in convective turbulence and to develop better models of this diffusion for a wide range of applications. Toward those ends, two diffusion problems are being studied in the Fluid modeling Facility (FMF) convection tank. The first concerns "transport asymmetry," the difference in the diffusion properties of scalars introduced at ... |
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| The Vertical Distribution of Heating in the Tropical Atmosphere |
28 SEP 93 |
12 pages |
| Authors:
William M. Frank; John L. McBride; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| The project has three major research goals: (1) Assist the planning of TOGA COARE; (2) Participate in the TOGA COARE field program; and (3) Carry out a research program using the TOGA COARE data set to examine the mean properties and vertical heating profiles of mesoscale and larger scale phenomena in the COARE region. The work will focus on exploring relationships between tropical weather systems in this region and larger ... |
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| Refractive Index Structure in the Lower Atmosphere |
AUG 93 |
34 pages |
| Authors:
J. Wyngaard; D. Thomson; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| We develop a local scaling theory for structure-function parameters of refractive index and velocity fluctuations in the stably stratified atmospheric boundary layer. The theory relates them to the local values of vertical temperature flux and shearing stress. The theory agrees well with data from observations and from large-eddy simulations. The effects of flow unsteadiness, baroclinity, terrain slope, and breaking gravity waves are apt to cause vertical profiles of to vary ... |
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| Development and Testing of Improved Techniques for Modeling the Hydrologic Cycle in a Mesoscale Weather Prediction System |
JAN 93 |
11 pages |
| Authors:
Thomas Warner; Toby N. Carlson; J. M. Fritsch; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| Soil-water content is the single most important land-surface variable in atmospheric prediction models. Sophisticated surface physics-soil hydrology parameterization schemes are beginning to be used in mesoscale weather prediction models; however, soil-water content is not measured over large enough areas on a regular basis where it could provide suitable initial conditions for those models. Therefore, the initialization of the soil-water content profile has to depend on a knowledge of the hydrological ... |
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| Boundary Layer Coherent Structures CY 1993 |
93 |
5 pages |
| Authors:
Hampton N. Shirer; George S. Young; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
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| SAR-Related Stress Variability in the Marine Atmospheric Boundry Layer |
30 SEP 92 |
113 pages |
| Authors:
Hampton N. Shier; George S. Young; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| Satellite- or aircraft-bourne synthetic aperture radars (SAR) have the potential to serve as a powerful and essential part of the global meteorological/oceanographic observation system. While the potential of SAR systems is enormous, quantitative interpretation of SAR signals has clearly been frustrated by our incomplete understanding of the relationships between the radar backscatter cross section and a complicated heterogeneous and constantly changing state of the sea surface. In the first phase ... |
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| The Vertical Distribution of Heating in the Tropical Atmosphere |
15 AUG 92 |
5 pages |
| Authors:
William M. Frank; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| The project is designed to achieve three major goals: (1) Assist the planning of TOGA COARE to optimize experimental design and measurement strategy, focussing on the larger scale arrays but paying particular attention to the problem of integrating the measurements from the arrays; (2) Participate in the TOGA COARE field program during the IOP; and (3) Carry out a research program examining the mean properties and vertical heating profiles of ... |
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| SAR-Related Stress Variability in the Marine Atmospheric Boundary Layer (MABL) |
92 |
8 pages |
| Authors:
Hampton N. Shirer; George S. Young; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| By stressing the sea surface, the marine atmospheric boundary layer (MABL) wind field can alter the sea surface wave field and so can produce discernable signatures on Synthetic Aperture Radar images of the ocean. Among the resulting signatures, the quasi-linear and cellular microscale patterns still require adequate explanation. The ubiquitous MABL two- and three- dimensional convective circulations provide promising candidates for the forcing phenomena producing these signatures. These microscale circulations ... |
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| SAR-Related Stress Variability in the Marine Atmospheric Boundry Layer (MABL) (High Resolution ARI) |
92 |
39 pages |
| Authors:
Hampton N. Shier; George S. Young; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| By stressing the sea surface, the marine atmospheric boundary layer (MABL) can alter the sea surface wave field and so can produce discernible signatures on SAR images of the ocean (e.g. Visecky and Stewart 1982). Among the resulting signatures, the quasi-linear and cellular microscale patterns still require adequate explanation. The ubiquitous MABL two- and three-dimensional convective circulations provide promising candidates for the forcing phenomena producing these signatures. These microscale circulations ... |
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| Modeling and Observational Studies of Mesoscale Air-Mass Boundaries and Warm-Season Convective Precipitation |
31 MAY 91 |
14 pages |
| Authors:
Thomas T. Warner; J. M. Fritsch; Toby N. Carlson; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| Diagnostic and modeling studies have been performed to improve our understanding of, and skill at forecasting, mesoscale weather systems and circulations, In particular, we have investigated: The effects of entrainment and detrainment on convective cloud heating and moistening profiles, The effects of mesoscale water bodies and ocean currents on the large scale environment and transient weather systems, The effect of subcloud-layer evaporative cooling and changes in radiatively produced surface fluxes ... |
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| The Measurement of Air-Sea Fluxes |
09 OCT 90 |
82 pages |
| Authors:
C. W. Fairall; George S. Young; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| This project involves the investigation of an indirect method of inferring surface fluxes of momentum, sensible heat and latent heat over the ocean. The work includes participation in the Humidity Exchange Over the Sea (HEXOS) program, a multinational project involving a series of field measurements and theoretical development. The air-sea fluxes are important physical processes which must be parameterized in climate, synoptic, mesoscale, and boundary layer and oceanic numerical models. ... |
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| Analysis of Significant Weather on Meso-Alpha Scales Using Conventional and Remotely-Sensed Data - Further Studies |
AUG 90 |
121 pages |
| Authors:
Gregory S. Forbes; Timothy Dye; Ming-Tzer Lee; Dennis W. Thomson; John J. Cahir; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| This report summarizes three M.S. Thesis research. Chapter 2 examines the atmospheric structures accompanying some meso-alpha-scale cloud patterns and the surface weather affiliated with them, via detailed analyses of wind fields involving time-space conversion of hourly profiler-measured horizontal winds and rawinsonde winds and temperatures. Chapter 3 summarizes a study using profiler three-dimensional winds at 5-minute intervals (or less) to examine the structure of meso-beta-scale precipitation bonds. In Chapter 4 winds ... |
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| A Case Study Using Kinematic Quantities Derived from a Triangle of VHF Doppler Wind Profilers |
Oct 1989 |
11 pages |
| Authors:
Catherine A Carlson; Gregory S Forbes; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| Horizontal divergence, relative vorticity, kinematic vertical velocity, and geostrophic and ageostrophic winds are computed from Colorado profiler network data to investigate an upslope snowstorm in northeastern Colorado. Horizontal divergence and relative vorticity are computed using the Gauss and Stokes theorems, respectively. Kinematic vertical velocities are obtained from the surface to 9 km by vertically integrating the continuity equation. The geostrophic and ageostrophic winds are computed by applying a finite differencing ... |
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| Analysis of Significant Weather on Meso-Alpha Scales Using Conventional and Remotely Sensed Data - Exploratory Studies |
JUL 89 |
229 pages |
| Authors:
Gregory S. Forbes; Dennis W. Thomson; John J. Cahir; Catherine A. Carlson; Paul J. Neiman; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| Studies have been made regarding the use of Doppler wind profiler data in weather analysis and forecasting. Wind profiler from the Fleming, CO and McAlevy's Fort, PA sites were used to examine a number of cases of subtle weather situations. Use of the wind profiler data, together with conventional National Weather Service rawinsonde data proved quite helpful in understanding the cause of subtle weather systems seen in either satellite imagery ... |
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| Long Term Studies of the Refractive Index Structure Parameter in the Troposphere and Stratosphere |
88 |
75 pages |
| Authors:
C. W. Fairall; D. W. Thomson; W. J. Syrett; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| This project studied the relation of meteorological conditions to parameters and processes that influence the optical propagation properties establishment of a climatology of refractive index structure function parameter as measured with a network of doppler radars. The relation of the atmospheric turbulence profile to the synoptic context and physical models to predict the profile using standard meteorological profile data was also being investigated. The study features two modes of data ... |
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| Anelastic Semigeostrophic Flow Over a Mountain Ridge |
OCT 1987 |
11 pages |
| Authors:
Peter R. Bannon; Pe-Cheng Chu; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| Scale analysis indicates that five nondimensional parameters (R(0) sq, epsilon, mu, lambda and kappa lambda) characterize the disturbance generated by the steady flow of a uniform wind (U0, V0) incident on a mountain ridge of width alpha in an isothermal, uniformly rotating, uniformly stratified, vertically semi-infinite atmosphere. Here mu = h(0)/H(R) is the ratio of the mountain height h(0) to the deformation depth H(R) = fa/N where f is the ... |
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| Kinematic Quantities Derived from a Triangle of VHF Doppler Wind Profilers |
AUG 87 |
|
| Authors:
Catherine A. Carlson; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
 | Using Data from a triangle of VHF Doppler wind profilers, various kinematic quantities are calculated to investigate the mesoscale and synoptic- scale wind structure of jet streams, upper-level fronts, and synoptic-scale troughs. Hourly winds are used to compute horizontal divergence, relative vorticity, vertical velocity, and geostrophic and ageostrophic wind velocities. Kinematic vertical velocities are obtained at levels from the surface to 9 km by vertically integrating the horizontal divergence, applying ... |
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| Mesoscale ST Doppler Radar Measurements at Pennsylvania State University |
01 OCT 86 |
|
| Authors:
Dennis W. Thomson; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| With substantial financial assistance from the USAF Office of Scientific Research, the Department of Meteorology at Penn State University has constructed and installed three clear-air Doppler St Profiler radars. Two of the radars (VHF) operate at approximately 49 MHz, the third (UHF) at about 405 MHz. The VHF systems are now permanently installed near McAlevey's Fort and Crown, Pennsylvania, respectively. The UHF is a portable system which can be either ... |
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| Sum Rules for Optical Extinction and Scattering by Small Particles |
10 AUG 86 |
|
| Authors:
Craig F. Bohren; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| The sum rule for extinction is not changed when magnetic dipole as well as electric dipole ration is considered. Moreover, the limitation of electron mean free paths in metallic particles does not invalidate sum rules. When metallic particles are sufficiently small, the effect of their boundaries is to decrease peak extinction while simultaneously broadening it in such a way that integrated extinction remains constant. |
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| Sum Rules for Optical Extinction and Scattering by Small Particles |
18 MAR 86 |
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| Authors:
Craig F. Bohren; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| The solution to the problem of scattering by an arbitrary homogeneous sphere (Mie theory) yields an infinite set of coefficients. These scattering coefficients depend on various Bessel functions and their derivatives. The usual approach to computing scattering coefficients is to compute the Bessel functions by recurrence. The Bessel functions in the expressions for the scattering coefficients satisfy recurrence relations. It has been shown that the scattering coefficients themselves satisfy recurrence ... |
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| Analysis and Prediction of Mid-Latitude Mesoscale Convection Precipitation Systems |
86 |
|
| Authors:
T. N. Carlson; J. M. Fritsch; T. T. Warner; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| This research focused on diagnostic and modeling studies of mesoscale processes associated with severe weather events. The work can be grouped into the following four areas: (1) Studies of the influence of surface forcing on convective storms; (2) Analysis and initialization of three-dimensional models; (3) Studies of the effects of elevated mixed layers on convective storms; and (4) General studies of the physical processes involved in the development and maintenance ... |
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| Diagnostic Aids and Analyses for Smaller-Scale Moisture Structure |
OCT 84 |
|
| Authors:
John J. Cahir; Gregory S. Forbes; Walter D. Lottes; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| An atmosphere model of the disturbed area sometimes found ahead of cold fronts in association with a low-level and upper-level jet is described. Use of the term 'moist conveyor belt' to describe this feature is suggested and a method for recognizing the feature with associated attributes is described. Polar lows and means of identifying synoptic scale environmental factors related to their development are also considered. Means of objectively locating air ... |
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| A Scheme for Short-Term Prediction of Hydrometeors Using Advection and Physical Forcing |
JUL 1984 |
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| Authors:
G. S. Forbes; J. J. Cahir; W. D. Lottes; E. Araujo; P. O. G. Heppner; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| We have developed a number of schemes which show skills varying from modest to impressive, depending upon the weather regime. These schemes are interactive, and their successful implementation requires a man-machine mix. The approaches taken in this research project have primarily focused upon the developmental or evolving, i.e. non-steady-state aspects of the problem of short-term forecasting of cloudiness and precipitation. Most of our schemes have incoporated a translational contribution either ... |
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| Development of a Technique for Short-Term Prediction of Hydrometeors Using Advection and Physical Forcing |
MAR 1983 |
|
| Authors:
Gregory S. Forbes; John J. Cahir; Paul B. Dorian; Walter D. Lottes; Kathy Chapman; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| This interim scientific report describes initial stages of a project to enable prediction of humidity and cloudiness in mesoscale areas and their short-term changes. The performance of the LFM-II humidity forecasts is evaluated as an indicator of large-scale humidity patterns and their changes. The usefulness of various meteorological parameters as potential predictors of cloudiness and cloudiness change is assessed through correlation studies. The predictor fields are compared to brightness and ... |
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| Analysis and Prediction of Severe Storm Environment |
FEB 1983 |
|
| Authors:
Toby N. Carlson; Thomas T. Warner; Michael J. Fritsch; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| The most significant aspect of this research regards the role of differential surface heating and topography in the development of mesoscale weather. Research has progressed in four areas: conceptual development, model development, model sensitivity tests, and prediction. The effect of surface heating and topography on precipitation and lid generation are forming the basis of current and on-going numerical and conceptual research. The effect of variations in soil moisture on the ... |
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| Validation of Bulk Turbulence Modeling in Stable Regimes |
AUG 1982 |
|
| Authors:
Robert E. Golus; Hans A. Panofsky; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| A special set of observations of wind, temperature and moisture over Lake Ontario has been used to test bulk methods for computing stress, heat flux, evaporation, and structure constants, over a wide range of stabilities. Reasonably good results were obtained for the structure constant of temperature (C sub T squared). Bulk methods overestimated directly-measured stresses by about a factor of 2, possibly because wind speeds and wave speeds did not ... |
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| Estimation of Vertical Wind Shear from Infrared and Microwave Radiances |
JAN 1982 |
|
| Authors:
Hans A. Panofsky; Anthony Cavalier; John J. Cahir; Frederick Gadomski; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| Linear regression estimates of radiosonde observed vertical wind shears between mandatory levels were made, using radiance gradients obtained via the TIROS-N satellite as predictors in a pilot experiment based on about 200-500 observations. The best results were obtained for shears between 850 mb and a level in the upper troposphere such as 300 mb. Results were similar for 850-400 or 850-200 mb shears, but notably inferior for 850-500 mb shears. ... |
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| Estimation of Vertical Wind Shear from Infrared and Microwave Radiances |
APR 1981 |
|
| Authors:
Hans A. Panofsky; John J. Cahir; Anthony Cavalier; Frederick Gadomski; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| Linear regression estimates of radiosonde observed vertical wind shears between mandatory levels were made, using radiance gradients obtained via the TIROS-N satellite as predictors in a pilot experiment based on about 200-500 observations. The best results were obtained for shears between 850 mb and a level in the upper troposphere, such as 300 mb. Results were similar for 850-400 or 850-200 mb shears, but notably inferior for 850-500 mb shears. ... |
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| The Role of Diabatic Heating in Generating Lower Tropospheric Mesoscale Circulations. |
31 DEC 1979 |
|
| Authors:
Thomas T. Warner; Richard A. Anthes; Nelson L. Seaman; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
|
| A two-dimensional, multilevel primitive equation model is used to investigate various characteristics of thermally driven circulations. The sensitivity of the mesoscale circulations to the magnitude of the surface, sensible heat flux is established through examination of various quantifiable circulation features such as the planetary boundary layer depth and the horizontal and vertical wind maxima. The simulations fall into two groups; one deals with circulations over flat terrain in the vicinity ... |
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| Effect of Improved Accuracy of Aircraft Reconnaissance Data in the Initialization of a Two-Dimensional Hurricane Model, |
01 NOV 1974 |
|
| Authors:
Richard A. Anthes; James E. Hoke; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
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| On the basis of a limited number of experiments, it appears that a significant improvement in a two-dimensional hurricane model's behavior results when the small errors associated with the proposed AWRS system are used instead of a system with temperature and wind errors about five times those of the AWRS system. The smaller errors associated with the new AWRS system are much less damaging; and the observations appear to be ... |
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| WIND PROFILES, SPECTRA, AND CROSS-SPECTRA OVER HOMOGENEOUS TERRAIN. |
30 JUN 1967 |
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| Authors:
Alfred K. Blackadar; H. Tennekes; Anton S. Chaplin; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF METEOROLOGY
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| Similarity principles of the flow in the surface layer of the atmosphere under neutral conditions are utilized herein to simplify the prediction of the wind profile below 200 meters in the planetary boundary layer. A method describing how the wind distribution in the diabatic boundary layer can in principle be determined is presented. A method describing how eddy exchange coefficients can be obtained from composite wind profiles is developed and ... |
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