Effects of Extreme Mountains on Extreme RainstormsPowerPoint PresentationSlide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Slide 45Slide 46Effects of Extreme Mountains on Extreme Rainstorms Robert A. Houze, Jr.withS. Medina, U. Romatschke, K. Rasmussen, S. Brodzik, D. Niyogi, and A. KumarGeology & Geophysics Colloquium, Yale, New Haven, CT, 17 November 2010Extreme mountain rangesHimalayasAndesRockiesPakistan Floods—Summer 2010"Almost 20 million people need shelter, food and emergency care. That is more than the entire population hit by the Indian Ocean tsunami, the Kashmir earthquake, Cyclone Nargis, and the earthquake in Haiti—combined.”Secretary-General Ban Ki-moonAugust 2010"Almost 20 million people need shelter, food and emergency care. That is more than the entire population hit by the Indian Ocean tsunami, the Kashmir earthquake, Cyclone Nargis, and the earthquake in Haiti—combined.”Secretary-General Ban Ki-moonAugust 2010Pakistan Floods—Summer 2010Types of rainstormsFrontal systems •midlatitude winter stormsTropical cyclones•hurricanes, typhoonsConvective storms•local thunderstorms•“mesoscale convective systems”Example of a local thunderstormViewed from the ground100 kmExample of a local thunderstormViewed from spaceOklahomaExample of a mesoscale convective systemThree MCSs1458GMT 13 May 2004ConvectivePrecipitationStratiformPrecipitationRadar echoes showing the precipitation in the 3 MCSsIdealized structure of a mesoscale convective systemHouze 1989Radar echoStratiformStratiform ConvectiveThe TRMM SatelliteThe TRMM SatelliteTRMMPrecipitation RadarLow altitude, low inclination orbitKummerow et al, 1998>>TRMM Precipitation RadarTRMM Precipitation RadarImportant! Radar measures 3D structure of radar echoesλ= 2 cmThe Himalayan regionA natural laboratory for studying the behavior of extreme convection near a huge mountain rangeIdentify each Identify each contiguouscontiguous 3D echo object 3D echo objectseen on radarseen on radarConvective componentConvective componentStratiform componentStratiform componentExtreme characteristicExtreme characteristicContiguous 3D volume ofContiguous 3D volume ofconvective echo > 40 dBZ convective echo > 40 dBZ Top height > 10 kmTop height > 10 km““Deep convective coreDeep convective core”” Horizontal area > 1 000 kmHorizontal area > 1 000 km22““Wide convective coreWide convective core””Extreme characteristicExtreme characteristicContiguous stratiform echoContiguous stratiform echowith horizontal area > 50 000 kmwith horizontal area > 50 000 km22““Broad stratiform regionBroad stratiform region””Radar Identification of Extreme RainstormsExamplesDeep Convective CoreWide Convective CoreBroadStratiformRegionConvectiveStratiformBased on 10 years of data for the monsoon season (JJAS)Deep Convective CoresWide Convective CoresBroadStratiformRegionsClimatology of extreme convective featuresEastern Himalayan regionRainstorms have -massive stratiform regions-which are enhanced by airflow over the mountainsSUMMER MONEX SUMMER MONEX 6 July 19796 July 1979850 mb windHouze and Churchill 1987SUMMER MONEXSUMMER MONEX 6 July 19796 July 1979NOAA P3 AircraftNOAA P3 Aircraft88E 92E14N20N14N20N88E 92EHouze and Churchill 1987MicrophysicsRadar100 km100 kmExtensive stratiform precipitation areasExample of a Bay of Bengal depression observed by Example of a Bay of Bengal depression observed by TRMM & simulated by WRFTRMM & simulated by WRFSurface windWRF simulationTotal RainMedina et al. 2010TRMM PRTRMM PRWRF SimulationWRF Simulation(a)Medina et al. 2010WRF Simulation SummaryWRF Simulation SummaryBlack -- 850 mb wind vectorsMedina et al. 2010White -- 850 mb heightWhite -- 850 mb heightYellow -- 500 mb vertical velocityBased on 10 years of data for the monsoon season (JJAS)Deep Convective CoresWide Convective CoresBroadStratiformRegionsClimatology of extreme convective featuresRECALLRECALLRECALLRECALLWestern Himalayan region•Severe local storms•Similarities to the region east of the Rocky MountainsCarlson et al. 1983Carlson et al. 1983Carlson et al. 1983Carlson et al. 1983moistdry,hotTexasSawyer 1947Sawyer 1947Sawyer 1947Sawyer 1947Consistent with Consistent with Sawyer 1947Sawyer 1947Consistent with Consistent with Sawyer 1947Sawyer 1947Consistent with Sawyer 1947Consistent with Sawyer 1947Backward trajectories (HYSPLIT/NCEP)2.5 km1.0 kmMedina et al. 2010WRF SimulationWater vapor(mixing ratio at surface)Potential buoyancy(“CAPE”)Medina et al. 2010Hydrometeor mixing ratio just after convection formed (water per mass of air)Isochrones of integrated hydrometeor contentMedina et al. 2010WRF SimulationFirst cloud formationTRMM PR Observations WRF SimulationMedina et al. 2010The Pakistan FloodsStorms of the eastern type occur in the west!Normal upper-level wind pattern for Pakistan stormsNormalWind pattern 28 July 2010: very abnormalNormalWind pattern 28 July 2010: very abnormalNormalNormalTime sequence…700 mb wind (~3 km)700 mb wind (~3 km)LLLLLLLLHHWater vapor anomaly500 mb windWater vapor anomaly500 mb windRainA humid environment was created in a dry placeTypical environmentFlood caseBengal casePressure (mb)1000500200Relative humidity (%)50 1000Temperature (C)040-401000500200Broad stratiform precipitation occurred over the mountains of PakistanBroad stratiform! Floods!East of the AndesAnother region of intense convection… Is it like convection near the Rockies and Himalayas?The geographyVertical air motionsVertical air motionsLow-level windsLow-level windsAverage airflow conditions for storms with wide convective coresdowndownupupmoistmoistunstableunstableExample of triggering over the Sierra Cordoba rangeWhat the storm looked like on the TRMM radarConclusions•Large mountain ranges affect extreme convective rainstorms by: •Channeling low-level moisture•Producing capping of the moist layer•Triggering convection•Enhancing the stratiform components of mesoscale convective systems•Processes occur in different combinations•Understanding them can help understand extreme events such as the Pakistan floodsEndThis research was supported byNSF grant ATM-0820586 and NASA grant