Differences between CCMP V1.1 and V2.0?


Differences between CCMP V1.1 and V2.0?

Postby dmoroni » Fri Jan 15, 2016 2:58 pm

What are the differences between the Cross-Calibrated Multi-Platform (CCMP) L3.0 ocean wind analyses V1.1 and V2.0 datasets?

For background information, please refer to the following pages for each dataset:
The first difference to note is that PO.DAAC only distributes the Version 1.1 dataset. Remote Sensing Systems (RSS) distributes the Version 2.0 dataset.

Without diving too deep into the details, perhaps the most important difference between V1.1 and V2.0 is the baseline calibration of the microwave radiometer and scatterometer sensor data that has been assimilated. V1.1 uses a variety of calibration versions throughout it's time series whereas Version 2.0 utilizes a consistent calibration known as RSS V7.

Furthermore, perhaps the next important issue is the change in the background analysis that is used. In V1.1, CCMP utilized the uropean Center for Medium-Range Weather Forecasts (ECMWF) Reanalysis ERA-40 as the background first-guess wind field from 1987 through 1998. From 1999 until 2011, V1.1 utilized the ECMWF Operational Analysis wind fields as the first-guess. With V2.0, CCMP utilizes the latest ECMWF Interim-Reanalysis as the first guess, which unlike the previous ERA-40 and Operational Analysis is processed on a consistent 0.25 degree grid. More information on the ECMWF Interim Analysis may be obtained here: http://www.ecmwf.int/en/research/climate-reanalysis/era-interim

Below is a summary of all other upgrades for V2.0 that are not present in V1.1:

  • Extension of the CCMP data set to July 2015 with plans to provide bi-annual extensions and updates to the dataset.
  • Addition of winds from new instruments: ASCAT Metop-A, AMSR2, and GMI.
  • Use of improved moored buoy data with better quality control, including winds from NDBC, TAO, TRITON, RAMA, PIRATA, and Canadian buoys.
  • Upgrade of the data file format to netCDF4 with CF-1.6 metadata.
  • Each daily file contains four 6-hourly wind analyses and self-describing metadata.
For more information on CCMP V2.0, please visit http://www.remss.com/measurements/ccmp or contact support@remss.com.
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Re: Differences between CCMP V1.1 and V2.0?

Postby dmoroni » Thu Mar 03, 2016 1:39 pm

Here is a link to a recent poster that provides a nice comprehensive listing of improvements in the CCMP Version 2.0 dataset entitled "Improvements & Advances to the Cross-Calibrated Multi-Platform (CCMP) Ocean Vector Wind Analysis (V2.0)": http://images.remss.com/papers/scott/Joel_Scott_Poster_AGUOS2016_ccmp_v2.0.pdf

This poster was presented at the 2016 Ocean Sciences Conference by lead author Joel Scott of Remote Sensing Systems (RSS). Co-authors include Frank Wentz (RSS), Ross Hoffman (Atmospheric and Environmental Research), and Robert Atlas (NOAA).
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