Medspiration user meeting, dec 4-6

Use of Medspiration and GHRSST data in the Northern Seas

Jacob L. Høyer & Søren Andersen

Center for Ocean and Ice,

Danish Meteorological Institute

Medspiration user meeting, dec 4-6

Outline

1. Existing operational SST analysis for the North Sea and Baltic Seas

2. New SST analysis for North Atlantic, with focus on the Greenland waters

3. Conclusions and recommendations to Medspiration

Medspiration user meeting, dec 4-6

SST analysis for the North Sea/Baltic Sea

• SST analysis using optimal interpolation• Developed under the FP 5 project ODON. • Operational for 3 years • Local covariances, in x.y and time • Multiplatform with satellite dependent error

estimates• Only nighttime data• Bias corrections from in situ comparisons• Current spatial resolution: 0.03 degrees• Data ingested: O&SI-SAF, AVHRR 2 km,

AATSR 1 km, (AMSR-E) • Future: to be delivered within the Mersea

project in netcdf format on an opendap server

Medspiration user meeting, dec 4-6

Regional covariances-Spatial correlations -+50 km in x and y, averaged for

100x100 km bins-Contour intervals 0.1

Medspiration user meeting, dec 4-6

OI validation

Predictions compared against independent satellite and in situ observations:

OI RMS erroroC

Number of observations

Satellite data

(every 36 obs)

0.69 30290

In situ data 0.80 16810

Theoretical OI error

0.77 All grid points

Satellite validation

In situ validationReference: Høyer & She, JMS, 2006

Medspiration user meeting, dec 4-6

Satellite error correlations

The satellite error is correlated in space, not in time

Satellite correlation

In situ correlation

SpaceTime

In situ correlation

Satellite correlation

Correlations are calculated where both satellite and in situ observations are available

German Bight test case:

Daily real-time corrections based on bouy observations show RMS error improvements of more than 0.2oC

Medspiration user meeting, dec 4-6

Applications of North Sea/Baltic Sea SST analysis

• Used for NWP high resolution setup• Used for assimilation into a North Sea/Baltic Sea 3D model. • Several assimilation schemes tried out, Ensemble Kalman,

simplified Kalman, simplified Kalman+OI SST• Best combination was a simplified Kalman filter + OI SST fields

Reference: Larsen, Høyer & She, JMS, 2006

Medspiration user meeting, dec 4-6

Extension of OI scheme to other areas

• To support the round the world danish expedition, Galathea 3, a high resolution 0.05 degrees analysis has been made to cover the cruise track.

• Onboard research is guided by SST fields

• Focus area is the Greenland waters

• Based on the OSI-SAF, Medspiration and GHRSST data (ATSR, AVHRR, AMSR-E, TMI, SEVIRI 5km, (MODIS high res ).

• Very easy to set up new areas

• Static bias corrections based upon comparisons with in situ observations

• Individual satellite errors from in situ comparisons

• Experimenting with temporal bias corrections

• Weekly reruns to include delayed data

Medspiration user meeting, dec 4-6

Galathea 3 route covered with high resolution SST analysis products

Areas with high resolution SST analysis

Aug. 2006 -> April 2007

Medspiration user meeting, dec 4-6

Presentation in Java and GoogleEarth

• www.satelliteeye.dk

•Todays analysis + other data

• ocean.dmi.dk

•30 days archive and animations

Medspiration user meeting, dec 4-6

Validation of the SST observations and the analysis

• Validation period: 2 months, Sep, Oct, 2006, North Atlantic Area

• In situ observations: Argo floats and buoy obs from GTS network.

• Nighttime satellite data

• Daily validation statistics produced

SST product N matchups

Bias Stderr

ATSR 330 0.12 0.36

SAF, NAR 28985 -0.22 0.77

AMSR-E 25121 -0.02 0.72

MODIS-A 36359 -0.76 1.2

NAVO-LAC 25583 -0.02 0.72

NAVO_GAC 16628 -0.02 0.67

OI SST NATL 47110 0.02 0.70

Medspiration user meeting, dec 4-6

Applications and future Applications• ”Assimilated” into the HYCOM

model of the North AtlanticFuture• Compare with OSTIA and

Medspiration analysis using DDS • Improve statistics near ice• Reference all satellite data to

one satellite (AATSR ?) • to make a very high resolution

Greeland/Arctic product

Medspiration user meeting, dec 4-6

MCS L4 SST products ? Arctic L4 from DMI and met.no

• Challenging with L4 SST analysis in the presence of ice and close to ice edges, with temporally dependent statistics along with changing ice extent

• Met.no and DMI have expertise and observations from the operational ice mapping services and with high latitude SST and level 4 generation

• Full arctic coverage with special emphasis on the Nordic Seas, Greenland waters (DMI) and around Svalbard + Barents Sea (Met.no)

• Data in full resolution from SAF O&SI and Medspiration/GHRSST follow on: AVHRR, AATSR, METOP, AMSRE and ice products

• Include Sea ice temperature ? when/if level 2 data will be available.

• Need for coordination and sharing of knowledge with other regional level 4 products

Medspiration user meeting, dec 4-6

Conclusions and Feedback

• Important with regional high resolution level 4 analysis, using regional covariances and error statistics.

• Ice information important and statistics in vicinity of ice

Feedback• Very nice with the common data format, continue please !! • Delay of several days on the AMSRE data • Elevated errors on Modis Aqua data ? • AATSR data look very good, but few measurements• Different quality flags, AATSR vs. e.g. AVHRR • Seviri 5 km hourly nighttime data look good