Global Precipitation Mission Paul Joe Meteorological Service of

Global Precipitation Mission Paul Joe Meteorological Service of Canada

Outline n n Global Precipitation Mission European GPM Canadian GPM Retrievals and Validation Canada

The GPM Mission Objectives n n n International Set of Cooperative Satellite Missions & Associated Scientific Research. Applications Programs Better Understand Global Water & Energy Cycle Obtain Improvements in Prediction of Significant Climate, Weather, & Hydrometeorological Processes ¡ ¡ Particularly Water Cycle Accelerations/Decelerations, Tropical Cyclones & Severe Storms, Flood Hazards, Seasonal Flood-Drought Conditions, Stores of Fresh Water Resources Canada

The GPM Concept OBJECTIVES • Understand horizontal & vertical structure of rainfall, its macro- & micro-physical nature, & its associated latent heating • Train & calibrate retrieval algorithms for constellation radiometers Core Satellite • Non-sun-synchronous orbit Core Constellation • Provide sufficient global sampling to significantly reduce uncertainties in shortterm rainfall accumulations • Extend scientific and societal applications Constellation Satellites • Pre-existing operational- experimental & dedicated ~ 65° inclination satellites with PMW radiometers ~400 km altitude • Revisit time • Dual frequency radar (NASDA) 3 -hour goal at ~90% of time X-Ka Bands (13. 6 -35 GHz) • Sun-synch & non-sun- synch ~ 4 km horizontal resolution orbits ~250 m vertical resolution 600 -900 km altitudes ~ 18 d. BZ MDS (CGPM 0 d. BZ ? ) • Multifrequency radiometer (NASA) Precipitation Validation Sites for Error Characterization 10. 7, 19, 22, 37, 85, (150/183 ? ) • Select/globally distributed ground validation “Super sites” (research quality radar, up looking radiometer-radar-profiler system, raingage-disdrometer network, & T-q soundings) (Snow) • Dense & frequently reporting regional rain gage networks (Snow, DSDs) • Microphysical aircraft measurements and field campaigns (ERAF, Cloudsat) Canada

Concept Implementation Canada

EGPM The EGPM mission goal is to retrieve precipitation with an emphasis on Europe and Canada. The EGPM mission will be an integral and essential component of the GPM constellation. § Improve the accuracy of global precipitation estimates with a focus on light rain and snowfall; § Improve global and regional NWP and climate model forecasts; § Improve the near-real-time monitoring of hazardous and flash-flood producing storms. Canada

EGPM/CGPM n n Focus on snow and light rain Increased sensitivity requirements ¡ ¡ n High Sensitivity Radar Sounding microwave channels Ground Validation ¡ Focus on solid precipitation Canada

EGPM/GPM and Precipitation EGPM will extend precipitation observations to high latitudes Canada

CDF’s of Snowfall and Light Rain Detection Requirements Rainfall Intensity Snowfall Intensity Occurrence Accumulation At higher latitudes: • larger fraction of precipitation is 'light' • percentage of solid precipitation high Canada

WMO/Eumetsat User Requirements Canada

Specific Situations Eumetsat Canada

EGPM User Requirements Canada

Observation Technique Needs Horizontal fields of precipitation Techniques Microwave imaging in 18 to 150 GHz windows Accuracy enhancement for light liquid and solid precipitation Microwave backscattering at 36 GHz Microwave radiometer Microwave sounding in 50 -60 GHz & 118 GHz bands High Sensitivity Profiles of precipitation EGPM instruments Precipitation Radar Active/passive microwave sensing well established Innovation: imaging + sounding + radar Canada

Retrieval Simulation Error at surface 86% 18, 23, 36 and 89 GHz: differentiation between rain and snow 61% + 150 GHz: estimates of rain and snow 38% + 50 -60 and 118 GHz: quantitative retrievals 13% + radar: accurate profile retrieval Reference Canada

Ground Validation Objectives n n n To scientifically verify and continuously improve satellite retrieval algorithms. To establish measurement uncertainties in precipitation retrievals. To pursue precipitation validation research -particularly of physical kind. To advance GV measurement technologies. To serve scientific clients who depend upon GV information in their research and applications, e. g. : ¡ ¡ near-realtime retrieval error characteristics for data assimilation error detection/reporting in instantaneous retrievals for algorithm developers Canada

Canada

GPM Continental Supersite Requirements & Concept n n n Provide physical validation and error statistics for algorithms; demand error statistics for all measurements at supersite. Provide data so that algorithms can develop diagnostics to identify sources of error. Perform basic science. Initial thrust would be to identify relationship between large scale variables and precipitation regime/precipitation structure. Science thrust would relate large scale parameters (low-level wind direction, CAPE, etc. ) to precipitation type (convective, stratiform, icebased, warm rain, etc. ). TRMM has taught us that biases in the satellite algorithms are not only due to systematic algorithm errors, but also by changing cloud properties. Need this information so that these types of errors can be minimized and serve as guidance for algorithms. Provide motivation for field measurements to address specific algorithms problems, biases, etc. Canada

Canada

An Example Europe n n n Various Precipitation Regimes Various National Weather Services Various Research Organizations Various Radar Networks Various Sites suited for Ground Validation ONE AIM: Ground Validation for GPM and EGPM Sodankylä Chilbolton Cabouw Bonn Palaiseau Cevennes. Vivarais Catalunya Oberpfaffenhofen Graz Rome Canada

Potential GV Supersites Cabouw Chilbolton Palaiseau Oberpfaffenhofen Rome Catalunya Graz Canada

Instrumentation of Supersites The proposed European supersites have excellent instrumentation and are well experienced in the development and operation of the systems and the organization of field campaigns. n n n Radar systems (S, C, X, Ka, W - Band) (Ku ? ) co-located systems, some systems are mobile (airborne, truck) Multi-frequency radiometer systems Lidar systems, ceilometers Windprofiler, RASS, Sodar Surface observations Disdrometers, rain gauges Rain gauge networks Operational radio sondes nearby Lightning detection systems Research aircraft. . . Canada

Spatial Representativeness Fundamental Measurement Validation Problem Radar Only Radar matched to rain gage Gage only What is the truth? Need for measurement AND physical validation of GPM! Canada

Current Status of Potential GPM Ground Validation Site Network Finland U. K. Canada Netherlands U. S. -- NASA-Land DOE/ARM-SGP Japan -- CRL-North Wakkanai Germany Austria France Italy Spain-Catalunya U. S. -- NASA-KSC South Korea Greece C China Israel West Africa (AMMA) Japan -- CRL-South Okinawa Taiwan India U. S. -- NASA-Ocean Kawajalein/RMI Brazil South Africa Existing or Potential GV Supersite Australia Existing or Potential Standard GV Site Canada

Snowfall Issues n n n n In situ - Measurements – wind effects Remote Sensing Technologies Snowfall measurement in mountainous regions; Snow bands off open water; Measurement of low intensity solid precipitation events; Solid precipitation over sea ice and ice covered Arctic Ocean; Depth & Snow Water Equivalent (Z-S relationship); Wind drift problem for snow. Canada

Snowfall Water Equivalent Analysis with Wind Corrections Canada

Physical Validation Drop Size Distributions DSD from POSS, JW and PMS Canada

Cloudsat Linkages n n n Cloudsat Mission is CGPM Pre-launch Algorithm development Cal-val strategy development test-bed for GPM ¡ n Cal-Val infrastructure the same (double the investment value) ¡ n n n Measurement and physical validation strategy testing Super sites, field campaigns, people High sensitivity VPRs Same radar technology GPM Pre-Launch Activities – NAST-M Canada

Summary n GPM ~2011 ¡ ¡ n EGPM/CGPM ¡ ¡ ¡ n Global precipitation measurements 3 hour, various spatial resolutions Constellation of radiometers, Core satellite with radar 65 o/87 o latitude Focus on snow and light rain Not selected as part of Earth Explorer/Opportunity Recommended for Earth. Watch/part of GEO strategy Cal/Val ¡ ¡ Measurement and Physical Validation Extensive instrumentation Focus on error characterization Little experience with snow Canada