Braun, Scott

English

NASA Technical Reports Server

1Page
Scott Braun
GPM Project Scientist
NASA Goddard Space Flight 
Center
Precipitation Measurement 
Missions Science Team Meeting
November 5, 2019
www.nasa.gov/gpm
Twitter: NASARain
Facebook: NASARain
GPM Status and Science
https://ntrs.nasa.gov/search.jsp?R=20200000889 2020-03-28T18:46:49+00:00Z
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The GPM Core Observatory
GPM Core Observatory: 
• Launched: Feb. 27, 2014
• 6 years of operations, with fuel to 
last to ~2033 
• All systems operating nominally
–Reaction wheel #2 failed in 2019
GPM Microwave Imager (GMI) 13 Channels, 
(Provided by NASA)
– Passive radiometer with excellent calibration
– 10VH, 19VH, 23, 36VH, 89VH, 166VH, 1833, 
7
– Provides measurements of precipitation (rain and 
snow) intensity and distribution over 885 km 
swath
– High spatial resolution (down to ~5km footprints) 
Dual-frequency Precipitation Radar (DPR), 
(Provided by JAXA)
– KuPR similar to TRMM, KaPR added for GPM
– Provides 3D measurements of precipitation 
structure, precipitation particle size distribution
– High spatial resolution (5km horiz.; 250m 
vertical) 
3Page
The GPM Constellation
GPM Constellation:
• Intercalibrated brightness 
temperatures
• Merged satellite products
• Improved knowledge of 
water cycle variability
• Improved prediction of 
floods, landslides & 
freshwater resources
11 sensors in current constellation
4Page
Mission Status
Spacecraft and instrument status: All systems are fully functional
RWA 2
RWA 3
RWA 4
RWA 5
• Reaction 
wheel #2 (of 5) 
stopped 
rotating on 
May 30, 2019. 
GPM Anomaly
Possible causes:
• Increased drag in ball bearings
• Resistive short in ceramic 
capacitor
• Short circuit in +5V logic 
device
• FOD in gap between rotor and 
stationary part of reaction wheel
5Page
Algorithm Updates
• Current algorithms
– All passive microwave products at Version 05 (V05)
– All radar, combined, latent heating, and multi-satellite products at V06
– Covers TRMM and GPM eras
• Radar team working with PPS on V06X radar products
– Algorithms adjusted to account for Ka across full Ku swath
– Will be released to as experimental product once ready
• Next algorithm reprocessing
– PPS exploring use of NetCDF due to commercialization of HDF5. Desire for 
V07 toolkit to use NetCDF4.
– V07 expected to begin in the 2021 time frame
6Page
Notional V07 Timeline
• Feb 2021 L1B Radar
L1B/Base/L1C GMI/TMI
• Mar 2021 L2/L3 GMI/TMI GPROF
• Apr 2021 L2/L3 TRMM/GPM Radar
L1C Partner radiometers
• May 2021 L2/L3 Combined
L2/L3 GPROF Partner radiometer
• June 2021 Begin GPM/TRMM V07 reprocessing
• Aug 2021 SLH/CSH
• Sept 2021 Begin IMERG reprocessing
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GPM Applications
Database of 8300 unique users highlight use of GPM data across six thematic application areas. 
Engagement with users through webinars, in person trainings, workshops, interviews, and 
reaching out through social media
Uses IMERG for estimating 
corrosion on wind turbines
IMERG and other precip
retrievals for agriculture and 
food security forecasting
Parametric insurance 
modeling of extreme events
GMI Tbs are assimilated into 
the forecasting models for 
improved estimates of initial 
conditions
8Page
Ongoing GPM GV Activities
Marquette 
Cold Season 
Supersite
IMPACTS (2020-2022)
Winter Storm Dynamics 
and Microphysics
GPM providing D3R and 
ground instrument 
support
Tracking Aerosol Convection 
Interactions Experiment (TRACER)
Summer 2021 Houston, TX
Primary Sponsor: DOE/ARM
NASA providing NPOL radar
GPM Cal/Val and Algorithm Symposium
March 24-26, 2020 Boulder, CO
Workshop Objectives:
• Identify GPM Algorithm Issues and Gaps
• Advance Collaboration between GV and 
Algorithms
• Identify Opportunities for Future GV Data 
Collection
• Identify Short-term (V07) and Long-term (V08+) 
action items and teams 
https://www.colorado.edu/event/calval2020/
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GPM Senior Review Proposal
• 2020 Senior Review Proposal 
• Should highlight recent accomplishments toward mission 
objectives:
– Advancing precipitation measurements from space (including microphysical 
properties and vertical structure information)
– Improving knowledge of precipitation systems, water cycle variability, and 
freshwater availability
– Improving climate modeling and prediction
– Improving weather forecasting and 4D reanalysis 
– Improving hydrological modeling and prediction
• Will identify top objectives for the next three years
– Processing at V07 across full DPR swath for Ku and Ka
– Evaluation of Level-4 (model assimilated) rainfall products
– IMERG upgrades
– Improved snowfall retrievals
– New ground validation activities
10Page
Hail Retrieval and Climatology from GPM
Dan Cecil1, Sarah Bang2, and Ken Leppert3
1: NASA Marshall Space Flight Center; 2: NASA Postdoctoral Program; 3: University of Louisiana-Monroe
≥2.5-cm Hail
Les
s L
ike
ly
Mo
re L
ike
ly
Above: (Right) Probability of hail as a function of 19- and 37-GHz measurements, normalized 
using tropopause height. From Bang and Cecil 2019. (Left) Map of estimated frequency of large 
(≥2.5-cm) hail events using GPM 19 and 37 GHz channels, and tropopause height. From Bang 
and Cecil 2019.
Right:
Measured (thick blue) 
and simulated GPM 
brightness temperatures 
for a Texas hailstorm. 
Adapted from Leppert
and Cecil 2019.
• Bang and Cecil (2019) combine 
TRMM and GPM 19-GHz and 37-GHz 
measurements to estimate the 
likelihood a storm has large hail
• Determined the frequency of 
occurrence of those storms. 
• Scaling by tropopause height used to 
mitigate overestimation of storms in the 
tropics.
• Leppert and Cecil (2019) tested 
sensitivity to precipitation microphysics 
for a Texas hail storm with extremely 
low GPM-observed brightness 
temperatures. 
• Explains why GPM measurements are 
not highly correlated with hail size – the 
number of hailstones is more important 
than their size.
11Page
Using GPM Rainfall and Latent Heating (LH) Data to Inform and Evaluate Deep 
Convection Simulation in the NASA GISS GCM (Elsaesser et al., 2020)
Pluses: Altitudes of
Peak Heating
CMIP5 (GISS-E2)                CMIP6 (GISS-E2.1)                  CMIP6 (GISS-E3)
12Page
All-Sky GPM Data in GEOS Weather Forecasts 
Impact per 
Observation
• Largest impact of GMI radiances in the Tropics
• Specific humidity improved in short term (0-
72 hour) forecasts (top, hatched indicates 
significance)
• Similar improvements occur in tropical mid 
and lower tropospheric temperature and 
winds (not shown)
• Other modeling and initialization improvements 
included in the GEOS upgrade extend these 
improvements into the medium range
• GMI is seen to have the highest impact per 
observation of all the radiance observation 
types, and the total impact of GMI (bottom) is 
comparable to a single Microwave Humidity 
Sounder instrument (not shown)
Min-Jeong Kim (GMAO/GESTAR)
13Page
GEOS-5 Assimilation Development and Products
• GEOS-5 assimilation of all-sky radiances from constellation 
members
– AMSU-A, MHS, ATMS
– SSMIS, AMSR2 in progress
• GPM Project at GSFC is investigating the potential for a future 
Level-4 product (model assimilated rainfall product)
– Horizontal resolution as low as 12.5 km, temporal resolution 30 minutes or 
better
– Want to compare skill to IMERG, MRMS
– Potential product could be released with one of two near-future retrospective 
reprocessings or eventual MERRA-3 product
14Page
IMERG Versus GEOS
GEOS Analyzed Surface precip (mm/hr) 
(Conventional, IR/MW clear sky data  + 
all-sky GMI and all-sky MHS data assimilated) 
IMERG
precipCal (mm/hr)
2018 
Typhoon 
Maria
15Page
IMERG Versus GEOS
GEOS Precipitation Analysis
0030 UTC July 06, 2018
IMERG Precipitation Analysis
0030 UTC July 06, 2018
16Page
GPM and IMPACTS 2020
Investigation of Microphysics and Precipitation of Atlantic 
Coast-Threatening Snowstorms (IMPACTS)
– PI Lynn McMurdie, University of Washington, deputy PIs G. 
Heymsfield (GSFC), J. Yorks, and S. Braun
GPM funded additions:
• Dual-frequency, dual-
polarized, Doppler radar 
(D3R) near UCONN
•Pluvio, disdrometer, other 
instruments
17Page
Summary
• GPM’s systems are all fully functional, with fuel to potentially last 
until ~2033.
• V07 reprocessing nominally scheduled for mid 2021
• IMPACTS suborbital campaign ongoing
• GSFC exploring model assimilated level-4 rainfall products based 
on recent advancements in all-sky assimilation in GEOS model
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•EXTRA SLIDES
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Im
pr
ov
e
D
eg
ra
de
GPM Microwave Imager FSOI 
by  Band
1 Aug – 30 Nov 2018
23.8 GHz
The FSOI metric can be used 
to illustrate the importance of 
the 23.8 GHz band 
• For FSOI, negative (positive) 
values indicate that the 
observations contributed to 
a forecast error reduction 
(increase)
• Negative is good
• Of the six bands used in our 
weather forecasting system, 
the 23.8 GHz band accounts 
for 47% of the total forecast 
impact from GPM/GMI 
Impact of 23.8 GHz on 24 Hour Forecasts
Largest beneficial 
impact
FSOI=Forecast Sensitivity-Observation Impact
Courtesy of W. McCarty
37V GHz
166V GHz
1833 GHz
1837 GHz
20Page
Two Heavy Rain Events
Derived rain rate
No 23.8 GHz data
Derived rain rate
Includes 23.8 GHz data
Percentage differences between
the two estimates
21Page
GES DISC support to PMM
● Services updates:
○ V06B IMERG in Giovanni for visual and analysis exploration
○ Level 2 GPM sub-setter (average download volume reduction >90%)
○ Level 3 re-gridder (re-grids to 33 different gridding schemes)
● Services available:
○ OPeNDAP: Hyrax, THREDDS, GDS; OGC WMS
● User assistance and outreach
○ On-site science expertise providing personal assistance and numerous data recipes on 
how to understand and access PMM data.
○ User training including webinars, workshops
● IMERG in the Cloud (Cumulus)
○ Co-located with other DAACs data for integrated discovery, access, analysis in the 
Amazon cloud
○ MERRA-2, AIRS Level 2 as well in FY20.
● Giovanni in the Cloud
○ Analytics framework for next generation data systems
○ > 500x performance improvements for extraction and analysis of long time series 
(1000s of time steps)
○ Permits third parties to add data and services to Giovanni analysis framework.
● Other services in development:
○ Time aggregation services, geoTIFF format conversion for GIS users
Subset of L2 GPM-DPR within 500 km of 
Typhoon Mangkhut eye using GrADS.
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All-Sky GPM Data in GEOS Weather Forecasts
• On 11 July 2018, the GMAO began 
assimilating GMI observations
• Assimilation of GMI radiances in 
real-time
• Active assimilation under all-sky 
situations
• Advanced methods were 
incorporated to optimize the use of 
these observations
• Adaptive thinning in the presence 
of clouds and precipitation (left, 
where warm colors indicate 
increased convective activity)
• Advances to underlying radiative 
transfer algorithm
• Incorporations of cloud ice, cloud 
liquid, rain, and snow into the 
solution
Min-Jeong Kim (GMAO/GESTAR)
23Page
Fuel Predictions to Date
Prediction Plus/Early
Mean/
Nominal
Minus
/Late
June-2015 05/2029 11/2039 06/2043
Nov-2015 03/2027 03/2035 08/2039
May-2016 06/2032 04/2037 10/2047
Nov-2016 08/2029 01/2035 10/2038
May-2017 12/2034 05/2036 02/2037
Nov-2017 08/2027 07/2032 08/2035
May-2018 03/2033 05/2035 03/2037
Nov-2018 11/2026 09/2033 11/2036
May-2019 03/2026 04/2033 01/2037
Current end-of-fuel date is April 2033


GPM Status and Science

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