Cross-monitoring of L4 SST fields
This presentation is the property of its rightful owner.
Sponsored Links
1 / 9

GHRSST XI Science Team Meeting 21-25 June 2010, Lima, Peru PowerPoint PPT Presentation


  • 60 Views
  • Uploaded on
  • Presentation posted in: General

Cross-monitoring of L4 SST fields in the SST Quality Monitor (SQUAM) http://www.star.nesdis.noaa.gov/sod/sst/squam/L4/. GHRSST XI Science Team Meeting 21-25 June 2010, Lima, Peru. Alexander Ignatov 1 , Prasanjit Dash 1,2 , Robert Grumbine 3

Download Presentation

GHRSST XI Science Team Meeting 21-25 June 2010, Lima, Peru

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Ghrsst xi science team meeting 21 25 june 2010 lima peru

Cross-monitoring of L4 SST fields in the SST Quality Monitor (SQUAM)http://www.star.nesdis.noaa.gov/sod/sst/squam/L4/

GHRSST XI Science Team Meeting21-25 June 2010, Lima, Peru

Alexander Ignatov1, Prasanjit Dash1,2, Robert Grumbine3

1NOAA/NESDIS, Center for Satellite Applications & Research (STAR), USA

2Colorado State Univ, Cooperative Institute for Research in the Atmosphere (CIRA), USA

3NOAA, National Centers for Environmental Prediction (NCEP), USA

1


Ghrsst xi science team meeting 21 25 june 2010 lima peru

Motivation for L4 cross-monitoring in SQUAM

  • The SST Quality Monitor (SQUAM) was “initially” designed to monitor L2 satellite SSTs for stability and consistency (cross-platform & cross-product), in NRT, by comparing them against several L4 SSTs. The L2 SSTs include GAC and FRAC SSTs from AVHRRs onboard multiple platforms :

    • NESDIS heritage Main Unit Task (MUT, 2001-pr)

    • NESDIS Advanced Clear-Sky Processor for Oceans (ACSPO, 2008-pr)

    • NAVOCEANO (2000-pr)

    • O&SI SAF MetOp-2 FRAC (2009-pr)

  • Comparison of L2 SSTs against “several” L4 SSTs, however, demonstrated significant differences between the L4 products themselves, which motivated to develop a dedicated L4-SQUAM.

2


Ghrsst xi science team meeting 21 25 june 2010 lima peru

Intended users of L4-SQUAM

  • L4-SQUAM complements other existing intercomparison (IC) systems and efforts (the list below is not exhaustive) :

    • GHRSST IC-TAG: http://www.ghrsst.org/The-Inter-Calibration-TAG-(IC-TAG).html

    • High-Res. Diag. Data Set : http://www.hrdds.net/ (local IC at ~250 locations)

    • NCOF Global SST IC : http://ghrsst-pp.metoffice.com/pages/latest_analysis/sst_monitor/daily/ens

  • L4-SQUAM is intended to provide quick diagnostics to the developers of L4 products, as well as the user community, to choose a suitable product.

  • Currently, L4-SQUAM includes “SIX” daily products:

    • Two daily 0.25º x 0.25º (lat/lon grid) OISST (aka Reynolds)

    • Two daily RTG (0.5º low resolution and 1/12º high resolution)

    • UKMO 0.05º OSTIA, and IFREMER 0.1º ODYSSEA

3


Ghrsst xi science team meeting 21 25 june 2010 lima peru

Method of L4 intercomparison in SQUAM

  • The IC is made on a global scale with modules to highlight zonal differences, by analyzing differences between daily L4 products (ΔL4), which are matched in space by using nearest neighbor interpolation.

  • The diagnostics are made available (with one day lag) at an interactive user-friendly web interface: http://www.star.nesdis.noaa.gov/sod/sst/squam/L4/

  • Tabs for L4 IC in SQUAM:

    • Maps

    • Histograms

    • Statistical time series (# of matches, minimum and maximum, mean, median, standard deviation, robust standard deviation, skewness, kurtosis, extreme values)

    • Hovmöller time series of zonal differences

4


Ghrsst xi science team meeting 21 25 june 2010 lima peru

Maps of ΔL4

OISST (AVHRR based) – OSTIA, 7-June-2010

  • Maps provide snapshot of differences, caused by different snow/ice, land/sea masks and inputs

  • More combinations of ΔL4 and different dates are available at L4-SQUAM webpage

5


Ghrsst xi science team meeting 21 25 june 2010 lima peru

Histograms of ΔL4

OISST (AVHRR based) – OSTIA, 7-June-2010

  • Time series of parameters annotated on such PDFs are used for IC and consistency checks

  • More combinations of ΔL4 and different dates are available at L4-SQUAM webpage

6


Ghrsst xi science team meeting 21 25 june 2010 lima peru

Time Series Mean of “L4 – reference L4”Reference L4:RTG low res.

  • Observations:

  • OISSTs track each other (some differences)

  • Cold bias in OSTIA in the beginning (2006)

  • Anomalous RTG high res. SST for a few days in end of Feb 2010

  • Seasonal differences between L4 SSTs show cyclic patterns

  • ODYSSEA generally followed OSTIA with anomalies in Apr-2008 (stopped since end of 2009 ?)

L4 SSTs – RTG low res.

DOI_AV: OISST (AVHRR based) DOI_AA: OISST (AVHRR, AMSR-E), RTG_HR: RTG high resolution

OSTIA: UK Met office ODYSSEA: IFREMER

  • Time series of other statistical parameters (Std Dev, Skewness etc.) and wrt other L4 SSTs are available at the L4-SQUAM webpage.

  • Additionally, interactive plots are also available which allow users to see the numerical values and focus on specific temporal coverage and L4 SSTs of particular interest (see L4-SQUAM web).

7


Ghrsst xi science team meeting 21 25 june 2010 lima peru

Timeseries zonal dependences

OISST (AVHRR based) – RTG low res.

  • Observations:

  • Seasonal differences in northern hemisphere high latitudes (OISST warmer)

  • Seasonal differences in northern hemisphere mid-latitudes (OISST colder)

  • Seasonal differences in northern hemisphere low latitudes (OISST colder); mutual consistency improved since 2007.

  • Also, minor differences are observed in other latitudes.

  • The differences are likely due to different treatment of land/sea/ice masks.

  • More combinations are available at L4-SQUAM web.

8


Ghrsst xi science team meeting 21 25 june 2010 lima peru

Summary and Future Work

  • L4-SQUAM currently monitors six daily L4 SSTs:

    • Two daily 0.25º x 0.25º (lat/lon grid) OISST products

    • Two daily RTG products (0.5º low resolution and 1/12º high resolution)

    • UKMO 0.05º OSTIA, and IFREMER 0.1º ODYSSEA products

  • In general, OISSTs are mutually consistent.

  • Also, RTG products are somewhat mutually consistent (to a lesser degree) and require further reconciliation. (Note that, the RTG low resolution is an OISST like product whereas RTG high resolution is based on a newer physical algorithm).

  • OSTIA and ODYSSEA SSTs show mutual consistency, however, ODYSSEA product has been somewhat unstable (stopped production ?).

  • General high latitude differences between various products are likely due to different treatment of land/sea/ice mask and should be reconciled by the developers of these products.

  • Future plans

    • Add GHRSST GMPE & NAVO K10 to L4-SQUAM

      • Work with L4 producers to reconcile different L4 SSTs

THANK YOU!

9


  • Login