Global Distributions of High-wind Occurrence over the Ocean

Japanese language

Global map images of high-wind frequency

Click links below to pdf files of high-wind frequency climatologies over 7 years.
*Images are very high resolution. When viewing pdf, please use scroll and zoom in!
3-month mean climatology figures (pdf)
frequency only (~500KB) full information (~1.8MB)
Dec-Jan-Feb Dec-Jan-Feb
Jan-Feb-Mar Jan-Feb-Mar
Feb-Mar-Apr Feb-Mar-Apr
Mar-Apr-May Mar-Apr-May
Apr-May-Jun Apr-May-Jun
May-Jun-Jul May-Jun-Jul
Jun-Jul-Aug Jun-Jul-Aug
Jul-Aug-Sep Jul-Aug-Sep
Aug-Sep-Oct Aug-Sep-Oct
Sep-Oct-Nov Sep-Oct-Nov
Oct-Nov-Dec Oct-Nov-Dec
Nov-Dec-Jan Nov-Dec-Jan
Annual mean climatology figures (pdf)
frequency only (~500KB) full information (~1.8MB)
Annual Annual

description

0.25x0.25 degree QuikSCAT wind data from September 1999 through August 2006 are used to calculate the frequency of surface high winds stronger than 20 m/s. The frequency is defined as the ratio (%; shown by color) of the number of high winds to the number of total valid wind observations. Observations are twice daily at the maximum. The data contaminated by rain or sea ice were removed before calculation. Two different scales are used (scale located at bottom) for the Northern and Southern Hemispheres.

Spatial variability of the high-wind frequency is associated with SST and coastal orography. Full information pdf below shows the frequency (color) along with SST climatology (contour), orography (shading over land), and the dominant direction of the high winds (if well-defined; arrows).

Note that 'annual' mean is the average over months during which the sea is not covered by ice. Black lines plotted in the annual-mean figure (left link) indicate 50% differences in the number of observations between March and September. Near Antarctica, for example, 'annual' mean may be reduced to 'summer-autumn' mean owing to winter/springtime sea ice cover.

Data Access: Monthly Frequency of High-wind Events

Global data on a 0.25 degree grid are available:

Example of wind data

Scatter diagram of the zonal and meridional wind components of (twice-) daily QuikSCAT observation shows distribution of wind vector. Circle in the scatter diagram denotes wind speed = 20 m/s.
*The accuracy of QuikSCAT wind is lower for very weak winds (a few m/s) and very high winds (>>20 m/s).

Published Paper


Sampe, T., and S.-P. Xie, 2007: "Mapping high sea winds from space: A global climatology" Bull. Amer. Meteor. Soc., 88, pp.1965-1978. Abstract (AMS Journals Online)     pdf (AMS Journals Online; ~6.9MB)
  This work is supported by NASA (National Aeronautics and Space Administration) and JAMSTEC (Japan Agency for Marine-Earth Science and Technology).