Using ASCAT Wind and Other Data in Marine Forecasting

1.0 Introduction » 1.2 About the Lesson

The case study presented in this lesson demonstrates the use of scatterometer wind and, to a lesser extent, altimeter significant wave height products in marine forecasting. The first part of the lesson reviews cold fronts and their impact on weather and sea state conditions. The second part, the case study, follows the passage of a cold front over the South Atlantic Ocean on 23 and 24 November 2013 when the Polarstern research vessel was transiting the area. Data from 25 November 2013 are used to summarize the case study and close out the event.

The case uses observational data, including MSG satellite imagery, radiosonde measurements, coded SYNOP (surface synoptic observations) reports, ship-based photographs, ASCAT scatterometer wind products, and Jason altimeter wave heights, to assess current conditions and evaluate the accuracy of wind and wave guidance from two models, the GFS and WAVEWATCH III.

Audience

The lesson is intended for operational marine forecasters, meteorologists, and meteorological technicians at coastal stations, as well as meteorology students. To get the most out of the lesson, learners should have a sound meteorological background, particularly about mid-latitude and cold front systems, and be familiar with the basic marine meteorological forecasting parameters used in South Africa. Learners should also be competent users of conventional satellite imagery, NWP model output, Skew-T sounding profiles, and other in situ observations.

It is recommended that all learners, regardless of whether or not they have used scatterometer and altimeter products before, take COMET’s 2015 lesson Using Scatterometer Wind and Altimeter Wave Estimates in Marine Forecasting before starting the case study. It explains the basics of scatterometers and altimeters, including what they are, how they work, and how to use and interpret the products. Questions related to that lesson are woven into the case.

Objectives

After going through the lesson, learners will be better prepared to use satellite scatterometer and altimeter measurements in addition to conventional observational and NWP data in marine forecast operations. More specifically, they will be able to:

  1. Describe cold fronts and their impact on sea surface conditions
  2. Describe the uses and advantages of scatterometer sea surface winds and altimeter significant wave heights in marine forecasting
  3. Interpret scatterometer wind data
  4. Use scatterometer winds and other observations to determine current weather and sea state conditions, adjusting marine NWP analyses and forecasts as needed