CHARACTERIZATION OF INTER-SATELLITE DIFFERENCES IN RETRIEVED RAINFALL Dr. F. Joseph (Joe) Turk Naval Research Laboratory, Marine Meteorology Division Monterey, CA 93943 (831)-656-4888 [email protected]Third IPWG Workshop Melbourne, Australia 23-27 October 2006
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CHARACTERIZATION OF INTER-SATELLITE DIFFERENCES IN RETRIEVED RAINFALL Dr. F. Joseph (Joe) Turk
CHARACTERIZATION OF INTER-SATELLITE DIFFERENCES IN RETRIEVED RAINFALL Dr. F. Joseph (Joe) Turk Naval Research Laboratory, Marine Meteorology Division Monterey, CA 93943 (831)-656-4888 [email protected]. Third IPWG Workshop Melbourne, Australia 23-27 October 2006. - PowerPoint PPT Presentation
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CHARACTERIZATION OF INTER-SATELLITE DIFFERENCES IN RETRIEVED RAINFALL
Dr. F. Joseph (Joe) TurkNaval Research Laboratory, Marine Meteorology Division
In light of program changes, launch delays, etc, the future microwave (MW) sensor suite likely to be composed of different sensor types (as it is today)
Radar/radiometer, different channels on MW radiometers, conical & cross track scanning instruments, spatial resolutions, etc.
Retrieved rainfall characteristics likely to be different between sensors – varying as a function of rainfall rate, latitude, season, background, etc.
Combining MW sensors is an ongoing research topic for GPM (in radiance space and rainfall space)
Data assimilation techniques may assimilate “rainy radiances” from a suite of inter-calibrated MW sensors; however,
High Resolution Precipitation Products (HRPP) will need to blend/merge these sets of disparate observations
Inter-Sensor Rainfall Characteristics
PEHRPP Suite 4: "Big picture" comparisonsPEHRPP Suite 4: "Big picture" comparisons (coordinator: ?)(coordinator: ?) Catch any artifacts not noticed in detailed statistics of above suitesCatch any artifacts not noticed in detailed statistics of above suites
• obvious systematic changes on a latitude line, related to availability of obvious systematic changes on a latitude line, related to availability of certain data typescertain data types
• changes in time series, related to data availabilitychanges in time series, related to data availability Validation of large-scale quantities and characteristics against bulk Validation of large-scale quantities and characteristics against bulk
quantities, existing products (GPCP, CMAP, etc.), streamflow data quantities, existing products (GPCP, CMAP, etc.), streamflow data sets, water budgets, and subjective judgment sets, water budgets, and subjective judgment
Focus on thousands of kilometers and monthly time scalesFocus on thousands of kilometers and monthly time scales
LOCAL OBSERVATION TIMES OF DMSP and NOAA SATELLITES
NOAA Satellites as of Late 2006Ascending Descending
0
6
12
18NOAA-15
NOAA-16
NOAA-18
NOAA-17
DMSP Satellites as of Late 2006Ascending Descending
0
6
12
18F-14
F-13
F-16
F-15
Dataset Preparation
Nearly three years (2004-current) of DMSP, NOAA, TRMM (WindSat since 6/06, Aqua since 4/05, F-16 since 2/06, NOAA-18 since 11/05)
From each orbit file, rain histogram is binned by date, latitude and surface (0.2 mm hr-1 steps)
First step is to analyze up-front rain/no-rain screening differences amongst various sensors
Second step is to analyze (non-zero) light rain differences
COLOR LEGENDNOAA-15 (AMSU)NOAA-16 (AMSU)NOAA-17 (AMSU)NOAA-18 (MHS)
winter summer winter summer
Seasonality signal not well represented at high latitudes
AMSU and MHS well-matched
Slight differences likely due to AM and PM crossing time
difference
summer winter summer winter
The Problem
• At the direction of US Strategic Command (USSTRATCOM) and in coordination with the NPOESS IPO-ADO for DMSP operations, the satellite operations control center activated the radar calibration (RADCAL) suite on DMSP F15, August 14, 2006.
• The RADCAL beacon operates at 150MHz & 400 MHz. On-orbit testing conducted in August 2005, confirmed that transmissions from the RADCAL 150Mhz Beacon produced interference in the SSMI 22GHz vertical polarization (22V) channel and that the 400Mhz Beacon interfered with SSMT-2 channel 4 performance.
• The SSMT-2 on F15 has since been declared "red" or non-operational due to an unrelated component failure.
• Users of the SSMI data must be aware that the 22V channel used in, ocean surface wind speeds, snow classification and depth, and rain rate calculations, etc., will be dramatically degraded during RADCAL Beacon transmission
Channel F-15 SSMI Mean TB
F-16 SSMIS Mean TB
F-15 SSMI Std Dev
F-16 SSMIS Std Dev
19V 198.7 199.4 13.3 13.2
19H 137.4 136.9 20.5 20.3
22V 237.5 225.9 22.2 21.8
37V 217.2 217.7 10.0 9.9
37H 162.6 162.3 18.3 18.0
85V 91V* 258.8 259.1 12.8 12.8
85H 91H* 231.3 230.7 24.0 23.7
F-15 and F-16 Intercomparison (Post-RADCAL)16 September 2006 Ocean-Only Center Beam Position
Data courtesy of Gene Poe, NRL
F-15 and F-16 synchronization:
F-13: 1833 localF-14: 1758 localF-15: 2010 localF-16: 2012 local
Good agreement at non-22 channels, max 0.7K difference
However, the statistics are dominated by no-rain pixels (~ 95%)
*85 GHz on SSMI, 91 GHz on SSMIS
DMSP F15-F1622V Channel Statistics
Pre-RADCAL01-13 August 2006
DMSP F15-F1622V Channel Statistics
Post-RADCAL15-28 August 2006
+/-70 Latitudes Over-Water
F-15RADCAL Beacon
Activated 14 Aug 2006
Impacts of Radcal Beacon Interference on F15 SSM/I Products
Saturated water vapor Missing clouds and precipitation