Dual Frequency Scatterometer (DFS) Dual Frequency Scatterometer (DFS) Partnership with JAXAPartnership with JAXA

Michael BrennanNational Hurricane Center

Richard KnabbCentral Pacific Hurricane Center2009 NOAA Hurricane Conference

Miami, Florida2 Dec 2009

QuikSCAT UpdateQuikSCAT Update

• QuikSCAT failed early on 23 November

• Spinning antenna stopped after a gradual degradation in performance over the past few months

• A remarkable mission of over 10 years in orbit

NOAA/NASA/JAXA PartnershipNOAA/NASA/JAXA Partnership• Japanese Space Agency (JAXA) planning GCOM-

Carbon cycle (GCOM-C) and GCOM-Water cycle (GCOM-W) missions– 13-year mission; three satellites in series, each with

5-year lifetime, 1-year overlap with follow-on satellites for calibration

– GCOM-W1 planned for launch late 2011, GCOM-W2 2016

• Since June 2008 NOAA, NASA/JPL, and JAXA have been discussing a potential partnership– U.S. would provide Dual Frequency Scatterometer (DFS),

designed by NASA/JPL on GCOM-W2 mission

NOAA/JAXA PartnershipNOAA/JAXA Partnership

Mary Kicza, assistant administrator for NESDIS, signed a Letter of Intent with Yasushi Horikawa, executive director of JAXA, agreeing to exchange data, conduct

joint research, and develop advanced integrated products. Both agencies plan to continue discussing the possibility of flying NOAA

instruments on future JAXA satellite missions.

Dual Frequency Scatterometer (DFS)Dual Frequency Scatterometer (DFS)• Builds on QuikSCAT and ASCAT heritage

• Ku-band (H-pol and V-pol) and C-band (H-pol) – Mitigates rain contamination

• Instrument design constrained by GCOM-W2 bus and AMSR instrument designs

• 1.8 to 2-m antenna– Basic resolution ~10 km

• 1800-km wide swath (identical to QuikSCAT)

• AMSR onboard with DFS provides opportunity to improve surface products (wind and SST) from both

Slice resolution16km x 3km 25-34km x 3km

HH

VV

DFS Design and CapabilitiesDFS Design and Capabilities• C-band channel retrievals

much less affected by rain• Experience with ASCAT

and DFS simulations show that adding C-band channel will yield substantial improvements over QuikSCAT retrievals in rain

DFS has capability to provide accurate DFS has capability to provide accurate retrievals in nearly all weather conditions, retrievals in nearly all weather conditions,

including Cat 1 and 2 hurricanesincluding Cat 1 and 2 hurricanes

DFS vs. QuikSCAT and XOWVMDFS vs. QuikSCAT and XOWVMSimulated Retrievals based on Katrina (2005)Simulated Retrievals based on Katrina (2005)

XOVWMQuikSCAT DFS

TS

H1

H2H3H4

H5

50

•DFS better captures true wind signal where QuikSCAT high winds are tied to rain

•DFS accurately depicts hurricane-force wind radii and retrieves winds into category 2 range, but not into category 3 range

•DFS cannot identify small scale wind maxima seen by XOVWM

“Truth”

DFS vs. QuikSCAT and XOWVMDFS vs. QuikSCAT and XOWVMKatrina Simulated RetrievalsKatrina Simulated Retrievals

•DFS captures true wind signal well into hurricane-force range•Significant improvement over QuikSCAT, where rain degrades quality of retrievals above around 50 kt

QuikSCATDFS

DFS vs. QuikSCAT and XOWVMDFS vs. QuikSCAT and XOWVMCoastal Retrievals – Shelikof Strait, AlaskaCoastal Retrievals – Shelikof Strait, Alaska

•DFS provides retrievals slightly closer to the coast compared to QS•Work underway that could provide retrievals from QuikSCAT and DFS within 6 km of the coast•DFS does not show large improvement seen in coastal XOVWM retrievals•Higher resolution of DFS does capture smaller-scale wind features not seen by QS

QuikSCAT DFS XOVWM

DFS Expected PerformanceDFS Expected Performance• Highest resolution of DFS 10 km compared to

12.5 km for QuikSCAT • DFS will improve wind retrieval accuracy over

QuikSCAT by at least 20%– Increased power, number of looks, frequency diversity,

larger aperture size

• At high wind speeds, DFS can improve accuracy up to 50%– Small-scale wind maxima in TCs still cannot be resolved,

but rain contamination mitigated

• No significant improvement in the distance to the coast achievable between QuikSCAT and DFS

Progress so far…Progress so far…• DFS accepted as a baseline instrument for

GCOM-W2• Research and Operational Users Working Group

(ROUWG) established (5 NOAA members)– Define mission requirements – Provide guidance on mission trade-offs between

instruments– Represent interests of research and operational

user communities– Advocate for mission, organize user meetings,

conference sessions, and solicit community input

DFS TimelineDFS Timeline• GCOM-W1 launch scheduled for Jan. 2011• GCOM-W2 launch scheduled for Jan. 2016• Timeline and funding uncertain from JAXA

side due to recent change in Japanese government– JAXA Mission Definition Review (MDR) for

GCOM-W2 has been postponed due to budget uncertainties

• Originally scheduled for Dec. 2009

• Likely to now be held early in 2010

Moving ForwardMoving Forward• Meeting scheduled launch date for GCOM W2 ‐

requires significant funding for DFS in FY11• FY10 House appropriations for NOAA and NASA

instructs agencies to work together to continue funding studies and instruct NOAA to make a request for funding in FY11 to build and fly a new operational scatterometer– Senate appropriation has no such language

• NWS and NOAA have briefed Congressional staffers on status of QuikSCAT and stated preference for DFS as a replacement

Scatterometry and ClimateScatterometry and Climate• Workshop held in DC during August 2009

– Participation from NOAA (NWS, NESDIS, OAR), NASA, JAXA, universities

• Goals– Provide a comprehensive case for the importance of continued

scatterometer measurements for climate studies and applications (including TC-climate relationships)

– Refine the climate requirements for the next-generation U.S. scatterometer, akin to the weather requirements already established by NOAA/NWS

• Workshop report nearing completion, and is intended for wide public distribution to help advocate for a next-generation U.S. scatterometer

Oceansat-2Oceansat-2• Indian Space Research

Ogranisation (ISRO) launched a research satellite, Oceansat-2, earlier this year, with a scatterometer on board similar to QuikSCAT

• NOAA, NASA, and ISRO signed a letter of intent on Nov. 18 to share Oceansat-2 data

• NOAA has agreed to explore making data downlink sites in Fairbanks and Wallops available to collect the data in near-real time

• Some hope that near-real time data could be available within a couple of years from this instrument

Gulfnews.com

Space News