NASA NTRS · 20230017757
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Walt Petersen, Courtney Schumacher, Patrick Gatlin. INCUS Ground Validation (Cal/Val). https://ntrs.nasa.gov/citations/20230017757
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Processes maintaining the localized maxima in lower stratospheric watervapor over the boreal summer Asian monsoon region are investigated usingtrajectory and cloud models that resolve the detailed cloudmicrophysical processes, with observation-based convection and radiationschemes. We examine the impact of convective influence along parceltrajectories on cloud formation and dehydration by tracing thetrajectories through time-dependent fields of convective cloud topheights estimated from global rainfall and geostationary brightnesstemperatures. Parameters such as the rainfall threshold used foridentification of deep convection are derived by comparison with theCloudSat deep convective cloud top product as enhanced by colocatedCALIOP measurements. The simulated water vapor field at the 100 hPalevel and cloud occurrence frequencies in the tropical tropopause layer(TTL) are constrained by corresponding observations from MLS andCALIPSO, respectively. The observed maximum in the 100 hPa level watervapor field over the Asian monsoon region is only present in thesimulation with convective influence, indicating the importance ofconvective hydration for the summertime water vapor distribution.Convection moistens the 100 hPa level over the Asian monsoon by 1 ppmv,where 75 of this moistening is due to convection occurring locallywithin the monsoon region. Convection also increases the cloudoccurrence frequency in the TTL over the southern sector of the Asianmonsoon anticyclone by 20. Parcels are convectively hydrated in thesoutheastern sector of the anticyclone, transported westward by theanticyclonic circulation, and dehydrated in the southwestern sector. Therelative importance of extreme convective events that inject ice andwater vapor near or above the tropopause will also be examined.
An overview of AF ATM Weather Research for Korean Airlines delegation. This was organized by NASA HQ. Will discuss previous work in aviation weather and discuss UTM weather.
Indirect evidence indicates a role for vertical mixing in the Tropical Tropopause Layer (TTL). In particular, detailed model studies suggest that such vertical mixing may be required to explain the value of the water vapor minimum in the TTL. There have been previous observations during the STEP Tropical aircraft campaign (1987) of bursts of high frequency activity associated with convectively generated gravity waves in the tropical western Pacific. Higher frequency, higher quality measurements from NASA high altitude aircraft (ER-2, WB-57, and Global Hawk) have been made available in the last 20 years. These include measurements of vertical velocity and other meteorological parameters. Most recently, during the ATTREX Global Hawk aircraft mission (Airborne Tropical TRopopause EXperiment), there have been extensive measurements at all altitudes of the TTL in both convective (winter western Pacific) and less convective (winter eastern Pacific) regions. This presentation represents an initial analysis of high frequency small scale (a few km max) meteorological measurements from the ATTREX dataset. We obtain some basic information about the distribution and character of high frequency activity in vertical velocity in the TTL. In particular, we focus on relating the high frequency activity to nearby tropical convection and to vertical shears associated with gravity and inertia-gravity waves.