RASI


Documentation



How to use the RASI site

This site enables you to easily search for, examine, and export data pertaining to Gap Wind or Sea Surface Temperature (SST) events for the following Central American regions from 1998-2011:

  • Tehuantepec
  • Papagayo
  • Panama

The site uses the terminology of "wind" and "SST" events. A "wind" event has been identified as an occurrence meeting criteria for a mountain gap wind for the particular location. An "SST" (sea surface temperature) event is a wind-induced upwelling of colder temperatures - and is identified by a temperature decrease within the study area.

To view a calendar displaying the duration of both wind and SST events, select View Events from the menu at the left. The calendar allows you to choose the location, month, and year of the event(s) you wish to examine. The red and blue bars represent the duration of detected SST and wind events, respectively, during the displayed time frame. By clicking on one of these colored bars, you will be able to examine a corresponding image of the wind or SST data for that region at the timeframe that was used for the event detection. Note there is only one SST temperature map per day representing the diurnally corrected SST, while CCMP winds are available four times a day; thus each day will have 4 wind images and 1 SST image associated with it.

To view corresponding wind and temperature parameters for event activity during a specific time and place, choose Get or Plot Data from the menu on the left. This will allow you to select the timeframe and location you are interested in, along with choosing the parameters of interest, and then either view the data in tabular form (by choosing "View Data") or as a customizable chart (by choosing "Plot Data"). Both the table and chart can be exported or saved to a variety of formats.


About the algorithm

You may read more about the algorithm used to identify and detect the wind and SST events shown on this site from the PDF "Method for Detecting Wind and Cold Water Upwelling Events from Satellite Data". The PDF includes references and is suitable for citing in other works.


About the project

RASI (Regional Air-Sea Interactions uses two satellite microwave-based data sets: the CCMP ocean surface wind data product and the RSS microwave OISST product.

The CCMP ocean surface wind data product is created using a 4-Dimensional variational analysis method (VAM) to combine wind measurements derived from SeaWinds on QuikSCAT, AMSR-E (Advanced Microwave Scanning Radiometer for EOS) on Aqua, TMI (Tropical Rainfall Measuring Mission's Microwave Imager) on TRMM, the series of SSM/I (Special Sensor Microwave/Imager) and SSMIS (Special Sensor Microwave/Imager Sounder) instruments on DMSP satellites, and WindSat on Coriolis.

The CCMP wind data set is distributed by the NASA Physical Oceanography Distributed Active Archive Center and contains a consistent data record of global high resolution (25 km) ocean surface winds for the period July 1987 through December 2010. This study uses the Level 3.0 First-Look (FLK) data set that contains 6-hourly gridded VAM analyses for 0, 6, 12 and 18 UTC. For this analysis, twelve years of CCMP data (1998 to 2011) were analyzed over Central America. We use the reduced period because SST data are also analyzed and satellite SST measurements did not start until 1998 with the launch of TRMM.

The microwave (MW) OISST product is produced by Remote Sensing Systems using TMI, AMSR-E, and WindSat SST measurements. TMI spatial coverage is 40N to 40S latitude and both AMSR-E and WindSat have near-global coverage. The spatial resolution of the OISST product is 25 km. These optimally interpolated satellite SST measurements are diurnally corrected and represent a daily 12 noon SST. The data are available from 1998 (launch of TMI) to present. We use data from 1998 to 2011 in this study.



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About RASI

RASI (Regional Air-Sea Interactions) is a tool for investigating Gap Wind and Sea Surface Temperature climatology.