Browsing by Author "Schumacher, Courtney"

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Convective multi-scale interactions over the Maritime Continent during the propagation of the MJO
Atmospheric Sciences; TAMU; https://hdl.handle.net/20.500.14641/651; DOC-NOAA-Climate Program Office
There are strong convective variations over the land and ocean regions of the MC. These land/ocean differences lead to strong diurnal variability in wind, clouds, and precipitation that also vary during the propagation of the MJO. Figure 1 (left panel) shows that the MC islands show a strong evening maximum with offshore propagation in the early morning. Figure 1 (right panel) shows that the diurnal cycle over land decreases sharply once the MJO begins traversing the MC (i.e., after phase 3), whereas the diurnal cycle over ocean shows less variation during the MJO propagation. The hypothesis of this work is that the diurnal cycle over land disrupts the convective evolution in the MJO envelope and that the MJO has to overcome this strong diurnal signal to make it through the MC unscathed.
Convective-Environmental Interactions in the Tropics
Atmospheric Sciences; TAMU; https://hdl.handle.net/20.500.14641/651; DOE-Office Of Science
During the four years of this grant performance, the PI and her research group have made a number of significant contributions toward better understanding convective processes over the Amazon. First, she made available to the broader community a two-year data set of convective storm metrics based on SIPAM radar data from the central Amazon that has been utilized widely. Second, her students analyzed cold pool and heating characteristics of Amazonian convection and showed in heretofore unknown ways how both can impact new convective initiation (e.g., through multiple cold pool interactions and gravity waves formed via pulsed heating). Finally, her group more broadly showed how Amazonian and Indian Ocean convection interacts with the large-scale environment, especially low-level winds (e.g., the nocturnal Amazonian low-level jet) and deeper tropospheric moisture, to help it organize and how this interaction is represented in climate models.
Evaluation of Climate Model Precipitation Processes using a TRMM/GPM Radar Simulator
Atmospheric Sciences; TAMU; https://hdl.handle.net/20.500.14641/651; NASA-Goddard Space Flight Center
The Cloud Feedback Model Intercomparison Project (CFMIP) Observation Simulator Package (COSP) will be adapted for Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) and Global Precipitation Measurement (GPM) dual-frequency precipitation radar (DPR) observations and applied to NASA GISS Model-E and other Coupled Model Intercomparison Project Phase 6 (CMIP6) general circulation model (GCM) grid-box output. The COSP sub-grid scale algorithm will be improved to align better with observations. We will comprehensively compare model-simulated observations to satellite-based radar reflectivity of precipitating cloud systems using the above radar simulator. Specifically, we aim to evaluate model fidelity at representing convective and stratiform precipitation processes and pinpoint possible causes for model-observation discrepancies. This research satisfies Section 2.3.2 Methodologies for Climate Model Improvement under Section 2.3 Data and Methodology for Climate Projection Assessment desire for “novel strategies and methodologies to compare results from Earth system models with NASA observations and reanalysis” and the goal to “identify any model systematic errors, associate the errors with model algorithm deficiencies, and pinpoint the necessary model improvements.”
Lightning-Environment Relationships
Atmospheric Sciences; TAMU; https://hdl.handle.net/20.500.14641/651; NASA-Washington
Lightning-environment relationships Recent results from ground and space-based radars have shown an early pick-up in convective rainfall with increasing tropospheric humidity, while stratiform rain has a later pick-up. However, the rainfall increase after the pickup is much stronger for stratiform rain because of its large areal coverage. This proposal will explore the lightning-moisture relationship, esp. in relation to the threshold that lightning begins to increase and how rapid the increase occurs. We will explore how this relationship varies geographically as the precipitation-moisture relationship shows significant variation between land and ocean and amongst continents and ocean basins. We will repeat the exercise for grid-scale omega. Environmental variables will come from NASA’S MERRA2 reanalysis and lightning data will be utilized from LIS and GLM. When available, we will use coincident rain information from the TRMM and GPM precipitation radars to link lightning properties to convective and stratiform rain intensity, areal coverage, and total accumulation. An ideal end result would be an understanding of what environmental conditions contribute most strongly to lightning onset and flash rate increase, how this varies between important regions in the global water cycle, including the ascending branches of the Walker and Hadley circulations, and if these conditions are associated with rainfall-environment relations, esp. in then extremes (e.g., high moisture and high omega).
Tropical Propagating Modes in the East Pacific ITCZ - Student: Lidia Huaman Chuquihauccha
Atmospheric Sciences; TAMU; https://hdl.handle.net/20.500.14641/651; NASA-Washington
Organized tropical cloud systems that evolve over synoptic (3-5 day) time scales play an important role in the overall precipitation in the Intertropical Convergence Zone (ITCZ). This project aimed to improve the understanding and prediction of convective systems associated with tropical propagating modes, including Kelvin and easterly waves, in the East Pacific ITCZ using NASA’s Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Measurement (GPM) satellites and NASA’s MERRA2 reanalysis as main tools. Additional emphasis was placed on how these propagating modes interact with the shallow and deep meridional overturning of the East Pacific, providing context for comparisons of convective interactions with meridional overturning in other tropical regions, like West Africa.