Gregory Tripoli - Academia.edu (original) (raw)
Papers by Gregory Tripoli
As a part of the Lake-Induced Convection Experiments (Lake-ICE), on December 21, 1997 the Univers... more As a part of the Lake-Induced Convection Experiments (Lake-ICE), on December 21, 1997 the University of Wisconsin Volume Imaging Lidar (UW-VIL) observed a visually stunning example of a shallow (~75-100 m) land breeze circulation over Lake Michigan. Backscatter returns revealed a steady offshore flow extending 1.5 to 4 km offshore, at which point it met the prevailing winds, which directly opposed the circulation. Since the prevailing onshore flow was weak enough to not overpower the local circulation, there was a consistent convergence zone offshore at the nose of the land breeze. Noting that the observed flow pattern is likely a simple combination of the large-scale atmospheric state and the local thermal forcing, we have simulated the day's events using a high -resolution version of the University of Wisconsin Non-Hydrostatic Modeling System (UW-NMS). The lidar data was used as a validation tool for the model output.
Weather and Forecasting, 1996
The authors evaluate the performance of current regional models in an intercomparison project for... more The authors evaluate the performance of current regional models in an intercomparison project for a case of explosive secondary marine cyclogenesis occurring during the Canadian Atlantic Storms Project and the Genesis of Atlantic Lows Experiment of 1986. Several systematic errors are found that have been identified in the refereed literature in prior years. There is a high (low) sea level pressure bias and a cold (warm) tropospheric temperature error in the oceanic (continental) regions. Though individual model participants produce central pressures of the secondary cyclone close to the observed during the final stages of its life cycle, systematically weak systems are simulated during the critical early stages of the cyclogenesis. Additionally, the simulations produce an excessively weak (strong) continental anticyclone (cyclone); implications of these errors are discussed in terms of the secondary cyclogenesis. Little relationship between strong performance in predicting the mass field and skill in predicting a measurable amount of precipitation is found. The bias scores in the precipitation study indicate a tendency for all models to overforecast precipitation. Results for the measurable threshold (0.2 mm) indicate the largest gain in precipitation scores results from increasing the horizontal resolution from 100 to 50 km, with a negligible benefit occurring as a consequence of increasing the resolution from 50 to 25 km. The importance of a horizontal resolution increase from 100 to 50 km is also generally shown for the errors in the mass field. However, little improvement in the prediction of the cyclogenesis is found by increasing the horizontal resolution from 50 to 25 km.
Bulletin of The American Meteorological Society, 2005
Title: The 9 10 November 2001 Algerian Flood: A Numerical Study. Authors: Tripoli, GJ; Medaglia, ... more Title: The 9 10 November 2001 Algerian Flood: A Numerical Study. Authors: Tripoli, GJ; Medaglia, CM; Dietrich, S.; Mugnai, A.; Panegrossi, G.; Pinori, S.; Smith, EA. Publication: Bulletin of the American Meteorological Society, vol. 86, Issue 9, pp.1229-1235. ...
Remote Sensing of the Atmosphere and Clouds III, 2010
ABSTRACT Based on the comparison of TMI measurements and the AWS rain rates, characteristics of r... more ABSTRACT Based on the comparison of TMI measurements and the AWS rain rates, characteristics of rain systems over the Korean Peninsula during summer were examined. It was found that the TMI brightness temperatures (TBs) at high frequency (85 GHz) are generally higher than those in GPROF database for the same rain rate. With these characteristics kept in mind, cloud resolving model simulations were performed by modifying intercept values in the Marshall-Palmer size distribution relationship. The intercept values of graupel and snow were assumed to twice the default value (snow: 1.0 × 108 m-4, Graupel: 4.0 × 106 m-4). Microwave brightness temperatures at passive microwave radiometer frequencies and vertical reflectivity at precipitation radar frequency are calculated by repeated application of the one-dimensional version of Eddington's approximation1. The hydrometeor profiles were selected by comparing with TRMM PR reflectivities. By adding those selected profiles to the convective profiles of GPROF database, we modified database for the rain retrieval over the Korean Peninsula. Rainfall retrievals by using the new database show that quality is significantly improved, indicating the need of algorithm locally more suitable.
Measuring Precipitation From Space, 2007
The purpose of the International Global Precipitation Measurement (GPM) Program is to develop a n... more The purpose of the International Global Precipitation Measurement (GPM) Program is to develop a next-generation space-based measuring system which can fulfill the requirements for frequent, global, and accurate precipitation measurements. The associated GPM Mission is being developed as an international collaboration of space agencies, weather and hydrometeorological forecast services, research institutions, and individual scientists. The design and development of the GPM Mission is an outgrowth of valuable knowledge and published findings enabled by the Tropical Rainfall Measurement Mission (TRMM). From the TRMM experience, it was recognized that the GPM Mission must consist of a mixed nonsunsynchronous and sunsynchronous orbiting satellite constellation in order to have the capability to provide physically based retrievals on a global basis, with ~3-h sampling assured at any given Earth coordinate ~90% of the time. The heart of the GPM constellation is the Core satellite, under joint development by NASA and the Japan Aerospace Exploration Agency (JAXA), which will carry a dual frequency Ku/Kaband precipitation radar (PR) and a high-resolution, multichannel passive microwave (PMW) rain radiometer. The core is required to serve as the calibration reference system and the fundamental microphysics probe to enable an integrated measuring system made up of additional constellationsupport satellites, each carrying at a minimum some type of PMW radiometer. In this article the background, planning, design, and implementation of the GPM is described.
Bulletin of the American Meteorological Society, 2000
Journal of The Atmospheric Sciences, 1986
Monthly Weather Review, 1979
ABSTRACT A numerical scheme to construct a two-way, movable, nested-mesh primitive equation model... more ABSTRACT A numerical scheme to construct a two-way, movable, nested-mesh primitive equation model is proposed. Dynamical coupling in a two-way nesting system is performed at a dynamical interface which is separated from a mesh interface by two coarse-grid ...
Journal of The Atmospheric Sciences, 1978
August 1978 WILLIAM R. COTTON AND GREGORY J. TRIPOLI 1503 Cumulus Convection in Shear FlowThree-... more August 1978 WILLIAM R. COTTON AND GREGORY J. TRIPOLI 1503 Cumulus Convection in Shear FlowThree-Dimensional Numerical Experiments William R. Cotton and Gregory J. Tripoli Department of Atmospheric Science, Colorado State University, Fort Collins 80523 ( ...
Monthly Weather Review, 1989
ABSTRACT The interaction of topographically induced thermally and mechanically driven diurnal flo... more ABSTRACT The interaction of topographically induced thermally and mechanically driven diurnal flow regimes in the lee of the Rockies is shown to lead to the growth of a mesoscale convective system (MCS). An orogenic MCS observed during the 1977 combined South ...
Monthly Weather Review, 1989
ABSTRACT The interaction of topographically induced thermally and mechanically driven diurnal flo... more ABSTRACT The interaction of topographically induced thermally and mechanically driven diurnal flow regimes in the lee of the Rockies is shown to lead to the growth of a mesoscale convective system (MCS). An orogenic MCS observed during the 1977 combined South ...
Monthly Weather Review, 1981
Journal of Applied Meteorology, 1980
ABSTRACT This study employs a revised version of the Colorado State University three-dimensional ... more ABSTRACT This study employs a revised version of the Colorado State University three-dimensional numerical cloud scale model to investigate the observed behavior of deep convection over South Florida on 17 July 1973. A brief description of recent model ...
Measuring Precipitation From Space, 2007
Precipitation occurring over the Mediterranean basin is typically unusually difficult to measure ... more Precipitation occurring over the Mediterranean basin is typically unusually difficult to measure due to variability resulting from the irregular terrain. Radar based precipitation measurements also are compromised by the terrain, which contaminates reflectivity with excessive ...
NEXRAD-In-Space (NIS) is a mission concept to provide a geostationary satellite Doppler radar. It... more NEXRAD-In-Space (NIS) is a mission concept to provide a geostationary satellite Doppler radar. It was developed over the last 4 years under the auspices of NASA's Earth Science Instrument Incubator Program (IIP). The NIS would provide Ka-band (35 GHz) reflectivity and line-of-sight Doppler velocity profiles over a circular Earth region of approximately 5200 km in diameter with a 12-km horizontal
Measuring Precipitation From Space, 2007
The purpose of the International Global Precipitation Measurement (GPM) Program is to develop a n... more The purpose of the International Global Precipitation Measurement (GPM) Program is to develop a next-generation space-based measuring system which can fulfill the requirements for frequent, global, and accurate precipitation measurements. The associated GPM Mission is being developed as an international collaboration of space agencies, weather and hydrometeorological forecast services, research institutions, and individual scientists. The design and development of the GPM Mission is an outgrowth of valuable knowledge and published findings enabled by the Tropical Rainfall Measurement Mission (TRMM). From the TRMM experience, it was recognized that the GPM Mission must consist of a mixed nonsunsynchronous and sunsynchronous orbiting satellite constellation in order to have the capability to provide physically based retrievals on a global basis, with ~3-h sampling assured at any given Earth coordinate ~90% of the time. The heart of the GPM constellation is the Core satellite, under joint development by NASA and the Japan Aerospace Exploration Agency (JAXA), which will carry a dual frequency Ku/Kaband precipitation radar (PR) and a high-resolution, multichannel passive microwave (PMW) rain radiometer. The core is required to serve as the calibration reference system and the fundamental microphysics probe to enable an integrated measuring system made up of additional constellationsupport satellites, each carrying at a minimum some type of PMW radiometer. In this article the background, planning, design, and implementation of the GPM is described.
Monthly Weather Review, 1975
An assimilation of satellite low-cloud vector data and conventional meteorological data is presen... more An assimilation of satellite low-cloud vector data and conventional meteorological data is presented. The domain of the study is the GATE A-scale area. The period is the summer months of 1972. Objective analysis of the data for 93 individual days was carried out for ...
Journal of the Atmospheric Sciences, 2007
... See appendix C for a description of the symbols used in this paper ... A two-dimensional idea... more ... See appendix C for a description of the symbols used in this paper ... A two-dimensional idealized (slab symmetric) simulation is implemented with UW-NMS ... UW-NMS (Tripoli 1992) is implemented as the 2D Eulerian CRM that integrates microphysical variables predicted by SHIPS ...
Journal of Geophysical Research, 2008
The omnipresent existence of thin, mixed-phase clouds in northern polar latitudes presents specia... more The omnipresent existence of thin, mixed-phase clouds in northern polar latitudes presents special challenges to CloudSAT as it attempts to map radiatively relevant cloudiness around the globe. In this work, retrieved cloud properties of Arctic mixed-phase clouds observed simultaneously in Eureka, Canada by ground-based cloud radar and lidar, and by the CloudSAT Cloud-Profiling Radar (CPR) are compared. Through these comparisons,
J. Climate Appl. …, 1986
The Colorado State University cloud model is applied to the simulation of orographic cloud snowfa... more The Colorado State University cloud model is applied to the simulation of orographic cloud snowfall. A model of ice crystal aggregation processes and primary nucleation and secondary ice particle production of crystals is described. Sensitivity ...
As a part of the Lake-Induced Convection Experiments (Lake-ICE), on December 21, 1997 the Univers... more As a part of the Lake-Induced Convection Experiments (Lake-ICE), on December 21, 1997 the University of Wisconsin Volume Imaging Lidar (UW-VIL) observed a visually stunning example of a shallow (~75-100 m) land breeze circulation over Lake Michigan. Backscatter returns revealed a steady offshore flow extending 1.5 to 4 km offshore, at which point it met the prevailing winds, which directly opposed the circulation. Since the prevailing onshore flow was weak enough to not overpower the local circulation, there was a consistent convergence zone offshore at the nose of the land breeze. Noting that the observed flow pattern is likely a simple combination of the large-scale atmospheric state and the local thermal forcing, we have simulated the day's events using a high -resolution version of the University of Wisconsin Non-Hydrostatic Modeling System (UW-NMS). The lidar data was used as a validation tool for the model output.
Weather and Forecasting, 1996
The authors evaluate the performance of current regional models in an intercomparison project for... more The authors evaluate the performance of current regional models in an intercomparison project for a case of explosive secondary marine cyclogenesis occurring during the Canadian Atlantic Storms Project and the Genesis of Atlantic Lows Experiment of 1986. Several systematic errors are found that have been identified in the refereed literature in prior years. There is a high (low) sea level pressure bias and a cold (warm) tropospheric temperature error in the oceanic (continental) regions. Though individual model participants produce central pressures of the secondary cyclone close to the observed during the final stages of its life cycle, systematically weak systems are simulated during the critical early stages of the cyclogenesis. Additionally, the simulations produce an excessively weak (strong) continental anticyclone (cyclone); implications of these errors are discussed in terms of the secondary cyclogenesis. Little relationship between strong performance in predicting the mass field and skill in predicting a measurable amount of precipitation is found. The bias scores in the precipitation study indicate a tendency for all models to overforecast precipitation. Results for the measurable threshold (0.2 mm) indicate the largest gain in precipitation scores results from increasing the horizontal resolution from 100 to 50 km, with a negligible benefit occurring as a consequence of increasing the resolution from 50 to 25 km. The importance of a horizontal resolution increase from 100 to 50 km is also generally shown for the errors in the mass field. However, little improvement in the prediction of the cyclogenesis is found by increasing the horizontal resolution from 50 to 25 km.
Bulletin of The American Meteorological Society, 2005
Title: The 9 10 November 2001 Algerian Flood: A Numerical Study. Authors: Tripoli, GJ; Medaglia, ... more Title: The 9 10 November 2001 Algerian Flood: A Numerical Study. Authors: Tripoli, GJ; Medaglia, CM; Dietrich, S.; Mugnai, A.; Panegrossi, G.; Pinori, S.; Smith, EA. Publication: Bulletin of the American Meteorological Society, vol. 86, Issue 9, pp.1229-1235. ...
Remote Sensing of the Atmosphere and Clouds III, 2010
ABSTRACT Based on the comparison of TMI measurements and the AWS rain rates, characteristics of r... more ABSTRACT Based on the comparison of TMI measurements and the AWS rain rates, characteristics of rain systems over the Korean Peninsula during summer were examined. It was found that the TMI brightness temperatures (TBs) at high frequency (85 GHz) are generally higher than those in GPROF database for the same rain rate. With these characteristics kept in mind, cloud resolving model simulations were performed by modifying intercept values in the Marshall-Palmer size distribution relationship. The intercept values of graupel and snow were assumed to twice the default value (snow: 1.0 × 108 m-4, Graupel: 4.0 × 106 m-4). Microwave brightness temperatures at passive microwave radiometer frequencies and vertical reflectivity at precipitation radar frequency are calculated by repeated application of the one-dimensional version of Eddington's approximation1. The hydrometeor profiles were selected by comparing with TRMM PR reflectivities. By adding those selected profiles to the convective profiles of GPROF database, we modified database for the rain retrieval over the Korean Peninsula. Rainfall retrievals by using the new database show that quality is significantly improved, indicating the need of algorithm locally more suitable.
Measuring Precipitation From Space, 2007
The purpose of the International Global Precipitation Measurement (GPM) Program is to develop a n... more The purpose of the International Global Precipitation Measurement (GPM) Program is to develop a next-generation space-based measuring system which can fulfill the requirements for frequent, global, and accurate precipitation measurements. The associated GPM Mission is being developed as an international collaboration of space agencies, weather and hydrometeorological forecast services, research institutions, and individual scientists. The design and development of the GPM Mission is an outgrowth of valuable knowledge and published findings enabled by the Tropical Rainfall Measurement Mission (TRMM). From the TRMM experience, it was recognized that the GPM Mission must consist of a mixed nonsunsynchronous and sunsynchronous orbiting satellite constellation in order to have the capability to provide physically based retrievals on a global basis, with ~3-h sampling assured at any given Earth coordinate ~90% of the time. The heart of the GPM constellation is the Core satellite, under joint development by NASA and the Japan Aerospace Exploration Agency (JAXA), which will carry a dual frequency Ku/Kaband precipitation radar (PR) and a high-resolution, multichannel passive microwave (PMW) rain radiometer. The core is required to serve as the calibration reference system and the fundamental microphysics probe to enable an integrated measuring system made up of additional constellationsupport satellites, each carrying at a minimum some type of PMW radiometer. In this article the background, planning, design, and implementation of the GPM is described.
Bulletin of the American Meteorological Society, 2000
Journal of The Atmospheric Sciences, 1986
Monthly Weather Review, 1979
ABSTRACT A numerical scheme to construct a two-way, movable, nested-mesh primitive equation model... more ABSTRACT A numerical scheme to construct a two-way, movable, nested-mesh primitive equation model is proposed. Dynamical coupling in a two-way nesting system is performed at a dynamical interface which is separated from a mesh interface by two coarse-grid ...
Journal of The Atmospheric Sciences, 1978
August 1978 WILLIAM R. COTTON AND GREGORY J. TRIPOLI 1503 Cumulus Convection in Shear FlowThree-... more August 1978 WILLIAM R. COTTON AND GREGORY J. TRIPOLI 1503 Cumulus Convection in Shear FlowThree-Dimensional Numerical Experiments William R. Cotton and Gregory J. Tripoli Department of Atmospheric Science, Colorado State University, Fort Collins 80523 ( ...
Monthly Weather Review, 1989
ABSTRACT The interaction of topographically induced thermally and mechanically driven diurnal flo... more ABSTRACT The interaction of topographically induced thermally and mechanically driven diurnal flow regimes in the lee of the Rockies is shown to lead to the growth of a mesoscale convective system (MCS). An orogenic MCS observed during the 1977 combined South ...
Monthly Weather Review, 1989
ABSTRACT The interaction of topographically induced thermally and mechanically driven diurnal flo... more ABSTRACT The interaction of topographically induced thermally and mechanically driven diurnal flow regimes in the lee of the Rockies is shown to lead to the growth of a mesoscale convective system (MCS). An orogenic MCS observed during the 1977 combined South ...
Monthly Weather Review, 1981
Journal of Applied Meteorology, 1980
ABSTRACT This study employs a revised version of the Colorado State University three-dimensional ... more ABSTRACT This study employs a revised version of the Colorado State University three-dimensional numerical cloud scale model to investigate the observed behavior of deep convection over South Florida on 17 July 1973. A brief description of recent model ...
Measuring Precipitation From Space, 2007
Precipitation occurring over the Mediterranean basin is typically unusually difficult to measure ... more Precipitation occurring over the Mediterranean basin is typically unusually difficult to measure due to variability resulting from the irregular terrain. Radar based precipitation measurements also are compromised by the terrain, which contaminates reflectivity with excessive ...
NEXRAD-In-Space (NIS) is a mission concept to provide a geostationary satellite Doppler radar. It... more NEXRAD-In-Space (NIS) is a mission concept to provide a geostationary satellite Doppler radar. It was developed over the last 4 years under the auspices of NASA's Earth Science Instrument Incubator Program (IIP). The NIS would provide Ka-band (35 GHz) reflectivity and line-of-sight Doppler velocity profiles over a circular Earth region of approximately 5200 km in diameter with a 12-km horizontal
Measuring Precipitation From Space, 2007
The purpose of the International Global Precipitation Measurement (GPM) Program is to develop a n... more The purpose of the International Global Precipitation Measurement (GPM) Program is to develop a next-generation space-based measuring system which can fulfill the requirements for frequent, global, and accurate precipitation measurements. The associated GPM Mission is being developed as an international collaboration of space agencies, weather and hydrometeorological forecast services, research institutions, and individual scientists. The design and development of the GPM Mission is an outgrowth of valuable knowledge and published findings enabled by the Tropical Rainfall Measurement Mission (TRMM). From the TRMM experience, it was recognized that the GPM Mission must consist of a mixed nonsunsynchronous and sunsynchronous orbiting satellite constellation in order to have the capability to provide physically based retrievals on a global basis, with ~3-h sampling assured at any given Earth coordinate ~90% of the time. The heart of the GPM constellation is the Core satellite, under joint development by NASA and the Japan Aerospace Exploration Agency (JAXA), which will carry a dual frequency Ku/Kaband precipitation radar (PR) and a high-resolution, multichannel passive microwave (PMW) rain radiometer. The core is required to serve as the calibration reference system and the fundamental microphysics probe to enable an integrated measuring system made up of additional constellationsupport satellites, each carrying at a minimum some type of PMW radiometer. In this article the background, planning, design, and implementation of the GPM is described.
Monthly Weather Review, 1975
An assimilation of satellite low-cloud vector data and conventional meteorological data is presen... more An assimilation of satellite low-cloud vector data and conventional meteorological data is presented. The domain of the study is the GATE A-scale area. The period is the summer months of 1972. Objective analysis of the data for 93 individual days was carried out for ...
Journal of the Atmospheric Sciences, 2007
... See appendix C for a description of the symbols used in this paper ... A two-dimensional idea... more ... See appendix C for a description of the symbols used in this paper ... A two-dimensional idealized (slab symmetric) simulation is implemented with UW-NMS ... UW-NMS (Tripoli 1992) is implemented as the 2D Eulerian CRM that integrates microphysical variables predicted by SHIPS ...
Journal of Geophysical Research, 2008
The omnipresent existence of thin, mixed-phase clouds in northern polar latitudes presents specia... more The omnipresent existence of thin, mixed-phase clouds in northern polar latitudes presents special challenges to CloudSAT as it attempts to map radiatively relevant cloudiness around the globe. In this work, retrieved cloud properties of Arctic mixed-phase clouds observed simultaneously in Eureka, Canada by ground-based cloud radar and lidar, and by the CloudSAT Cloud-Profiling Radar (CPR) are compared. Through these comparisons,
J. Climate Appl. …, 1986
The Colorado State University cloud model is applied to the simulation of orographic cloud snowfa... more The Colorado State University cloud model is applied to the simulation of orographic cloud snowfall. A model of ice crystal aggregation processes and primary nucleation and secondary ice particle production of crystals is described. Sensitivity ...