Bjorn Lambrigtsen Jet Propulsion Laboratory - California Institute of Technology...
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Bjorn Lambrigtsen Jet Propulsion Laboratory - California Institute of Technology [email protected] Propulsion Laboratory fornia Institute of Technology dena, California nasa.gov This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology under a contract with the National Aeronautics and Space Administration. Copyright 2008 California Institute of Technology. Government sponsorship acknowledged A “Geostationary A “Geostationary AMSU” AMSU” Hurricanes & severe storms 55-GHz warm core anomaly (continuously, in real time) Surface pressure anomaly = Intensity Equivalent radar reflectivity (continuous coverage of entire life cycle) Intensification/weakening, microphysics, convective structure Complete diurnal-cycle observations (< 15-minute time resolution) Model improvements Real-time atmospheric stability indices (including under full cloud cover) Severe storm warnings, tornado precursor detection AMV-inferred wind vectors (regardless of cloud cover) Improved forecasts Synergies Complement GEO IR sounders (cloud clearing) Complement LEO sounders (swath-gap & temporal-gap filling) Complement GEO imagers (resolution enhancement of MW) Global Precipitation Mission (provide spatio-temporal continuity) Key component of GPM “super-constellation” Technology Proof-of-concept prototype- demonstrated in 2005 The GeoSTAR prototype ational Aeronautics and Space Administration • Antenna size is determined by distance and “spatial resolution” • AMSU antenna is 6” in dia. and gives 40-km resolution from 705 km • GEO orbit is ~37000 km ≈ 50 x 705 km • AMSU-antenna must then be 50 x 6” to give 40-km res. from GEO • This is 25 feet (8 meters)! Can’t be done! • To get 50-km res. we need 20 feet. Still can’t be done •Solution: Synthesize large antenna GeoSTAR Low-earth-orbiting MW sounder (AMSU) Key element: The antenna Principle of aperture synthesis Science Dissecting hurricanes: 3D internal structure Height resolved “Radar reflectivity” Use radar algorithms to derive • Precipitation rate • Ice water path • Convective intensity • Vertical structure Vertical slicing through hurricane Emily - July 17, 2005 Scattering index - HAMSR water vapor channels 0.0 0.2 0.4 0.6 0 50 100 150 200 250 300 Distance [km] 167: 3-4km 183±3: 8km 183±1:10km EDOP HAMSR Nadir along-track view 2 km Scan swath view MW sounder Is equivalent to radar! Correlation between MW-sounder Tb and radar reflectivity exceeds 90% at all levels except near surface Inferred from HAMSR 3 km 4 km 5 km 6 km 7 km 8 km 9 km 10 km 11 km 12 km 13 km 14 km 15 km M atureproducts: Parameter Ho rizontal Vertica l Tem poral Accuracy Tb (5 0 GHz) 50 k m (6 c hannels) 3 min per ch. < 1/3 K Tb (18 3 GHz) 25 k m (4 c hannels) 5 min per ch. < 1/3 K Tem pera ture 50 k m 2 km 20min 1.5-2 K W ater vapor 25 k m 2 km 20min 25% Liquid water 25 k m 3 km 20min 40% Stabili ty index 50 k m N/A 20min N/A TPW 25 k m N/A 20min 10% LW C 25 k m N/A 20min 20% SST 100 k m N/A 1 hour < 0.5 K Evolving experimen tal products: Parameter Ho rizontal Vertica l Tem poral Accuracy Rain rate 25 k m N/A 20min 2 mm /hr Convect.intens. 25 k m N/A 20min N/A IWC 25 k m N/A 20min 30% W ind vector 25 k m 2 km 30min TBD Data products It works! Outdoor scene (far field) Indoor scene (near field) Calibration “Near Field range”, JPL GeoSTAR ”Earth” target Temperature controlled pads Computed from model Measured with GeoSTAR |Obs - Calc| < 2 K (Will be improved as system processing is optimized) Calibration facility at JPL: Earth-like disc viewed against cold-sky background mimicking Earth-view from GEO Develop Math model Assimilate Compare Obser- vations Initialize Adjust Forecast Models and observations Weather & climate models are deficient Cloud formation, convection & precipitation is not completely understood; “microphysics” is deficient Diurnal-cycle variations are not well modeled; storm life cycles are not well modeled Observations used to “feed” models are incomplete Most satellite sensors do not penetrate clouds nor observe the internal “microphysics” of clouds & storms Most satellites provide only brief snapshots twice a day, when the satellite passes overhead Therefore, we need… Continuous observations of the entire process: diurnal cycle, storm cycle, Observations under all weather conditions Improve Applications Numerical weather prediction (regional/global NWP) —Assimilation of radiances; 4DVAR applications Hurricane now-casting (15-minute refresh cycle) —Intensity assessment, detect rapid intensification/weakening —Observation of internal dynamics, kinematics & microphysics Severe storm development (cloudy observations) —Atmospheric stability (CAPE, LI, etc.) in cloudy regions —Detect/assess tornado precursor conditions Weather hazard assessment (continuous observations) —Life cycle storm observations; total rainfall —Predict/observe flood conditions Climate studies (stable sensor with “legacy continuity”) —Continuous time series; diurnal cycle fully resolved —Basin-scale intra-seasonal to interannual analyses —Cross-calibration of LEO climate sensors & data series Temperatur e sounding channels Water vapor sounding channels Physical basis of microwave sounding Absorption spectrum Weighting functions Simulated brightness temperature images (tropospheric temperature sounding channels) Ready to build! Many accommodation options Currrent estimate mass = 230 kg power = 340 W BW = 1 Mbps Fly GeoSTAR on GOES-R/S/T?
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Transcript of Bjorn Lambrigtsen Jet Propulsion Laboratory - California Institute of Technology...
Bjorn LambrigtsenJet Propulsion Laboratory - California Institute of Technology
Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadena, Californiawww.nasa.gov This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology under a contract with the National Aeronautics and Space Administration. Copyright 2008 California Institute of Technology. Government sponsorship acknowledged
A “Geostationary AMSU”A “Geostationary AMSU”
Hurricanes & severe storms 55-GHz warm core anomaly (continuously, in real time)
Surface pressure anomaly = Intensity Equivalent radar reflectivity (continuous coverage of entire life cycle)
Intensification/weakening, microphysics, convective structure Complete diurnal-cycle observations (< 15-minute time resolution)
Model improvements Real-time atmospheric stability indices (including under full cloud cover)
Severe storm warnings, tornado precursor detection AMV-inferred wind vectors (regardless of cloud cover)
Improved forecasts
Synergies Complement GEO IR sounders (cloud clearing) Complement LEO sounders (swath-gap & temporal-gap filling) Complement GEO imagers (resolution enhancement of MW) Global Precipitation Mission (provide spatio-temporal continuity)
Key component of GPM “super-constellation”
Technology
Proof-of-concept prototype- demonstrated in 2005
The GeoSTAR prototype
National Aeronautics and Space Administration
• Antenna size is determined by distance and “spatial resolution”• AMSU antenna is 6” in dia. and gives 40-km resolution from 705 km• GEO orbit is ~37000 km ≈ 50 x 705 km• AMSU-antenna must then be 50 x 6” to give 40-km res. from GEO• This is 25 feet (8 meters)! Can’t be done!• To get 50-km res. we need 20 feet. Still can’t be done•Solution: Synthesize large antenna GeoSTAR
Low-earth-orbiting MW sounder (AMSU)
Key element:The antenna
Principle of aperture synthesis
Science
Dissecting hurricanes: 3D internal structure
Height resolved “Radar reflectivity” Use radar algorithms to derive• Precipitation rate• Ice water path• Convective intensity• Vertical structure
Vertical slicing through hurricane Emily - July 17, 2005
Scattering index - HAMSR water vapor channels
0.0
0.2
0.4
0.6
0 50 100 150 200 250 300Distance [km]
Fractional Tb depression
167: 3-4km183±3: 8km183±1:10km
EDOP
HAMSR
Nadir along-track view
2 km
Scan swath view
MW sounderIs equivalent
to radar!
Correlation between MW-sounder Tb and radar reflectivity exceeds 90% at all levels except near surface
Inferredfrom
HAMSR
3 km
4 km
5 km
6 km
7 km
8 km
9 km
10 km
11 km
12 km
13 km
14 km
15 km
Mature products: Parameter Horizontal Vertical Temporal Accuracy
Tb (50 GHz) 50 km (6 channels) 3 min per ch. < 1/3 K Tb (183 GHz) 25 km (4 channels) 5 min per ch. < 1/3 K Temperature 50 km 2 km 20 min 1.5-2 K Water vapor 25 km 2 km 20 min 25% Liquid water 25 km 3 km 20 min 40%
Stability index 50 km N/A 20 min N/A TPW 25 km N/A 20 min 10% LWC 25 km N/A 20 min 20% SST 100 km N/A 1 hour < 0.5 K
Evolving experimental products: Parameter Horizontal Vertical Temporal Accuracy Rain rate 25 km N/A 20 min 2 mm/hr
Convect. intens. 25 km N/A 20 min N/A IWC 25 km N/A 20 min 30%
Wind vector 25 km 2 km 30 min TBD
Data products
It works!
Outdoor scene(far field)
Indoor scene(near field)
Calibration
“Near Field range”, JPL
GeoSTAR
”Earth” target
Temperaturecontrolled
pads
Computed from model
Measured with GeoSTAR
|Obs - Calc| < 2 K(Will be improved as system processing is optimized)
Calibrationfacilityat JPL:
Earth-like disc
viewedagainst
cold-skybackground
mimickingEarth-viewfrom GEO
Develop
Mathmodel
AssimilateCompare
Obser-vations
InitializeAdjust
Forecast
Models and observations
Weather & climate models are deficientCloud formation, convection & precipitation is
not completely understood; “microphysics” is deficient
Diurnal-cycle variations are not well modeled; storm life cycles are not well modeled
Observations used to “feed” models are incomplete
Most satellite sensors do not penetrate clouds nor observe the internal “microphysics” of clouds & storms
Most satellites provide only brief snapshots twice a day, when the satellite passes overhead
Therefore, we need…Continuous observations of the entire process:
diurnal cycle, storm cycle, Observations under all weather conditions GeoSTAR!
Improve
Applications Numerical weather prediction (regional/global NWP)
—Assimilation of radiances; 4DVAR applications
Hurricane now-casting (15-minute refresh cycle)
—Intensity assessment, detect rapid intensification/weakening—Observation of internal dynamics, kinematics & microphysics
Severe storm development (cloudy observations)
—Atmospheric stability (CAPE, LI, etc.) in cloudy regions—Detect/assess tornado precursor conditions
Weather hazard assessment (continuous observations)
—Life cycle storm observations; total rainfall—Predict/observe flood conditions
Climate studies (stable sensor with “legacy continuity”)
—Continuous time series; diurnal cycle fully resolved—Basin-scale intra-seasonal to interannual analyses—Cross-calibration of LEO climate sensors & data series
Temperature
soundingchannels
Water vaporsoundingchannels
Physical basis of microwave sounding
Absorption spectrum
Weighting functions
Simulated brightness temperature images(tropospheric temperature sounding channels)
Ready to build!Many accommodation options
Currrent estimate
mass = 230 kgpower = 340 WBW = 1 Mbps
Fly GeoSTAR on GOES-R/S/T?
