Impact of microphysical parameterizations on simulated storm evolution and remotely-sensed characteristics

A non-hydrostatic, three-dimensional cloud model was used in conjunction with a radiative transfer model to study the sensitivity o f the model-simulated storms and their remotely-sensed characteristics to the microphysical parameterizations used in the cloud model. Understanding the sensitivity o f the cloud-radiation databases to the assumptions that went into their building is o f particular importance since such cloudradiation databases are extensively used in the development o f algorithms for retrieval o f rainfall and latent heating from microwave observations o f precipitating systems. This study was conducted with the intent to shed more light on how the microphysical parameter choices affect not just a particular storm characteristic but the storm's microand macro-structure and evolution. Three types o f sensitivity tests were performed. The first evaluated sensitivity to the choice o f microphysical parameterization scheme. For that purpose tw o microphysical schemes were compared - Tao's and Perrier's. Both schemes share the parameterizations. Their main differences are in the treatment of the cloud ice initiation processes and the subsequent growth of snow. The second test evaluated the sensitivity of modeled storms to the selection of ice aggregation parameters and to the assumed number of ice crystals that are activated at 0° C. The third test evaluated the sensitivity of simulated storms to the selection of the hydrometeor’s descriptive parameters (density, terminal velocity, and particle size distributions). The storm dynamics and remotely—sensed characteristics are affected by the microphysical parameterization philosophies and by the choice of microphysical parameters and hydrometeor descriptive parameters. Different storm characteristics show sensitivity to different microphysical assumptions. This rinding suggests that by using coincidental observations of a variety of storm characteristics it would be possible to discriminate between simulations and to determine what microphysical setup produces storms that compare best to observations. Being able to reproduce the storm in its entirety will indicate that the complex intercorrelations between the different processes and scales are, indeed, properly represented by the model. This in turn, will give a high fidelity in the rainfall and latent heating retrieval algorithms using cloud model databases

Convective variability associated with a mesoscale vortex in a midlatitude squall line system

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references.The relationship between the kinematic structure of the convective line and the mesoscale stortn-relative flow associated with an embedded mesovortex in the trailing stratiform region of the 28 May 1985 squall line system is examined using Doppler radar data collected during the Preliminary Regional Experiment for Stonnscale Operational and Research Meteorology-Centml Phase (PRE-STORM). Ten dual-Doppler analyses of the kinematic and reflectivity fields are constructed for roughly a 50-minute period over the storrif s mature stage. Reflectivity and flow fields exhibit significant variability along the convective line. Large, somewhat isolated reflectivity cores, elongated in the direction of storm propagation, were located in the southern and central portions of the storm. In contrast, the northern part of the convective line was characterized by smaller, more closely spaced reflectivity cores which were organized perpendicularly to the storm propagation vector. Deepest reflectivity cores and strongest vertical drafts were consistently found on the southern flank of the system. The southern end of the convective line expanded during the analysis period while the convective intensity of the northern end of the line continuously decreased. A well organized cyclonic mesovortex was found at midlevel in the stratiform cloud trailing the north-central portion of the leading convective line. The variability in the structure of the convective cers along the convective line appeared to be related to the interaction between the mesoscale low-level outflow from this vortex and the environmental low-level inflow. The outflow was opposite the environmental inflow in the southern and central portions of the storm. In contrast, the outflow was directed nearly parallel to the inflow along the northem portion of the storm system. This led to variation in the depth and direction of propagation of the convective downdraft outflow such that there was greater low-level convergence and enhanced lifting in the southern and central portions of the convective line compared to the northem part. Hence, the variability in convective structure appears to have resulted from a scale interaction between the storm-induced relative flow and the environmental winds

Tropical Cyclone Information System

The JPL Tropical Cyclone Infor ma tion System (TCIS) is a Web portal (http://tropicalcyclone.jpl.nasa.gov) that provides researchers with an extensive set of observed hurricane parameters together with large-scale and convection resolving model outputs. It provides a comprehensive set of high-resolution satellite (see figure), airborne, and in-situ observations in both image and data formats. Large-scale datasets depict the surrounding environmental parameters such as SST (Sea Surface Temperature) and aerosol loading. Model outputs and analysis tools are provided to evaluate model performance and compare observations from different platforms. The system pertains to the thermodynamic and microphysical structure of the storm, the air-sea interaction processes, and the larger-scale environment as depicted by ocean heat content and the aerosol loading of the environment. Currently, the TCIS is populated with satellite observations of all tropical cyclones observed globally during 2005. There is a plan to extend the database both forward in time till present as well as backward to 1998. The portal is powered by a MySQL database and an Apache/Tomcat Web server on a Linux system. The interactive graphic user interface is provided by Google Map

A Multi-center exercise on the sensitivity of PAZ GNSS Polarimetric RO for NWP modelling

Trabajo presentado al 7th International Workshop on Occultations for Probing Atmosphere and Climate y al 9th Workshop of the International Radio Occultation Working Group (OPAC-IROWG), celebrados del 8 al 14 de septiembre de 2022 en Leibnitz, Austria.A better understanding of the thermodynamics of heavy precipitation events is necessary towards improving weather and climate models and quantifying the impact of climate variability on precipitation. However, there are limited observations available to assess the model structure within heavy precipitation conditions. Recently, it has also been shown that the Radio Occultations Through Heavy Precipitation (ROHP) GNSS polarimetric radio occultation (GNSS PRO) observations are highly sensitive to hydrometeors above the freezing layer, which expands the potential uses of the GNSS PRO dataset for weather-related science and applications. An exercise is presented to analyze the sensitivity of PRO observations for NWP modeling applications. The ROHP experiment now provides over four years of coincident thermodynamic and precipitation information with high vertical resolution within regions with thick clouds. Murphy et al. (2019) simulated GNSS airborne polarimetric RO (GNSS PRO) events along an atmospheric river. These were modeled by the community WRF mesoscale model using two different microphysical parameterization schemes. The GNSS PRO observables simulated with the two schemes differed significantly, more than the actual GNSS PRO precision. The new exercise presented here reproduces this methodology for spaceborne data, using different global and regional NWP models, and it analyzes the results and divergences with the help of actual GNSS PRO data acquired aboard the PAZ satellite. The objectives of the activity are: (1) To compare simulated GNSS PRO observables, generated with models from different centers and different microphysics schemes, against actual PAZ GNSS PRO observables. Can the models reproduce the main features of the actual data? (2) To assess whether different models/schemes result in different GNSS PRO observables, and whether these differences are larger than the measurement uncertainty. This effort provides insight on future methods to assimilate the PRO profile alongside other conventional (non-polarimetric) RO data. (3) To examine the utility of PAZ GNSS PRO observations for model validation and diagnosis. The exercise includes comparisons with ECWMF reanalysis ERA-5 model, the operational NWP at the Japan Meteorological Agency, and a near-real-time implementation of the WRF regional model over the northeastern Pacific produced at the Center for Western Weather and Water Extremes (CW3E) called West WRF, among others.The ROHP-PAZ project is part of the Grant RTI2018-099008-B-C22 funded by the Spanish Ministry of Science and Innovation MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe” of the “European Union”. Part of the investigations are done under the EUMETSAT ROM SAF CDOP4. This work was partially supported by the program Unidad de Excelencia María de Maeztu CEX2020-001058-M. Part of this research has received funding from the postdoctoral fellowships program Beatriu de Pinós, funded by the Secretary of Universities and Research (Government of Catalonia) and by the Horizon 2020 program of research and innovation of the European Union under the Marie Sklodowska-Curie grant agreement No 801370.Peer reviewe

Theoretical Modeling of Dual-Frequency Scatterometer Response: Improving Ocean Wind and Rainfall Effects

International Ocean Vector Winds Science Team Workshop (2017 IOVWST), 2-4 May 2017, San Diego, CaliforniaPeer Reviewe

Interpretation of the Precipitation Structure Contained in Polarimetric Radio Occultation Profiles Using Passive Microwave Satellite Observations

Collections: Precipitation Retrieval Algorithms for GPMObservationally, a major source of uncertainty in evaluation of climate models arises from the difficulty in obtaining globally distributed, fine-scale profiles of temperature, pressure, and water vapor that probe through convective precipitating clouds, from the boundary layer to the upper levels of the free troposphere. In this manuscript, a 2-yr analysis of data from the Radio Occultations through Heavy Precipitation (ROHP) polarimetric radio occultation (RO) demonstration mission onboard the Spanish Paz spacecraft is presented. ROHP measures the difference in the differential propagation phase delay (¿¿) between two orthogonal polarization receive states that is induced from the presence of nonspherically shaped hydrometeors along the Global Navigation Satellite System (GNSS) propagation path, complementing the standard RO thermodynamic profile. Since ¿¿ is a net path-accumulated depolarization and does not resolve the precipitation structure along the propagation path, orbital coincidences between ROHP and the Global Precipitation Measurement (GPM) constellation passive microwave (MW) radiometers are identified to provides three-dimensional precipitation context to the RO thermodynamic profile. Passive MW-derived precipitation profiles are used to simulate the ¿¿ along the ROHP propagation paths. Comparison between the simulated and observed ¿¿ are indicative of the ability of ROHP to detect threshold levels of ray-path-averaged condensed water content, as well as to suggest possible inferences on the average ice-phase hydrometeor nonsphericity. The use of the polarimetric RO vertical structure is demonstrated as a means to condition the lower-tropospheric humidity by the topmost height of the associated convective cloud structure.The work conducted at ICE-CSIC/IEEC was supported by the Spanish Grant ESP2015-70014-C2-2-R. The research was funded by the Spanish Ministry of Science, Innovation and Universities Grant RTI2018-099008-B-C22/AEI/10.13039/501100011033/FEDER, EU. The contribution from EC has been partially supported by the Radio Occultation Meteorology Satellite Application Facility (ROM SAF) which operated under the auspices of EUMETSAT. The JPL authors acknowledge support from the NASA U.S. Participating Investigator (USPI) and Geodesy program elements. JDN is supported in part by National Science Foundation Grant AGS-1936810