IR - WV Wind Comparison

June-July 2003
Go to IR-IR Comparison

Infrared and water vapor winds were plotted on various satellite images over the poles where interesting cases, such as cyclones, were found. A qualitative comparison was then done to find if coincident IR and WV winds existed. If so, the vectors from that time period were input to the matlab script, IR_WV2.m, where each IR wind was compared with the WV winds.

Approximately 2-3 water vapor winds were found for each IR wind within distance and height [pressure] specified thresholds. RMS differences in wind speed and direction were computed for coincident winds that fell within these two thresholds. The mean distance, pressure, speed, and direction were also computed using this dataset of points within the thresholds.

Histograms are plotted of the wind speed and wind direction differences with the frequency the value occurred and scatter plots are plotted of speed differences versus the different thresholds. Distances, pressures and speeds are computed by subtracting WV winds from IR winds. Direction difference is positive for WV winds clockwise of IR winds and negative for WV winds counter-clockwise of IR winds.

NOTE: Data is taken with a distance threshold of 50 km and pressure threshold of 25 mb unless otherwise specified.

Day/Time new thres	Pole/Satellite	# of points within thresholds	speed rms (m/s)	IR spd nrms	direction rms	mean dist diff	mean pres diff	mean spd diff	mean dir diff
153/0710	NP/TERRA	125	3.6	0.12	10.1	30.1	5.2	-0.5	0.2
153/0850	NP/TERRA	84	4.1	0.26	14.3	29.3	11.3	-0.9	-1.1
153/1030	NP/TERRA	72	3.9	0.17	12.4	31.2	-1.7	1.5	3.3
153/1205 75 km	NP/TERRA	78 149	2.9 3.6	0.18 --	11.0 13.4	28.5 --	7.1 --	0.2 --	2.0 --
153/1345 50mb	NP/TERRA	278 471	3.9 4.1	0.19 --	12.4 11.9	29.3 --	5.2 --	0.3 --	-1.2 --
153/1230	NP/AQUA	154	3.8	--	13.4	30.5	2.9	-0.1	2.6
153/1410	NP/AQUA	59	3.8	--	13.4	31.0	3.6	1.0	1.1
154/0050	SP/AQUA	1538	3.8	0.21	13.4	30.3	-1.2	0.1	-1.1
154/0230	SP/AQUA	1753	3.7	0.19	12.9	30.1	0.4	0.0	0.1
188/1730	Meteosat-7	1352	2.4	0.12	8.2	24.4	1.4	-0.2	0.1
195/2245	GOES E	5591	2.6	0.19	9.7	26.6	1.0	-0.4	0.3

Day/Time new thres	Pole/Satellite	# of points within distance but not within pressure threshold	speed rms (m/s)	direction rms
153/0710	NP/TERRA	1882	9.8	49.8
153/0850	NP/TERRA	2131	7.5	38.5
153/1030	NP/TERRA	2711	6.5	33.1
153/1205 75 km	NP/TERRA	2087 4552	6.3 6.3	33.2 34.7
153/1345 50mb	NP/TERRA	2834 2641	7.8 8.0	30.6 31.5
153/1230	NP/AQUA	3027	8.7	20.8
153/1410	NP/AQUA	3566	8.2	25.0
154/0050	SP/AQUA	3984	5.1	17.0
154/0230	SP/AQUA	3206	5.2	20.1

Histograms and Scatter Plots

Day/Time	Data within distance and pressure thresholds	Data within distance threshold but not pressure threshold	Speed vs Dist & Pres
153/0710	Speed Difference Direction Difference	Speed Difference Direction Difference
153/1345	Speed Difference Direction Difference	Speed Difference Direction Difference
188/1730 Meteosat-7	Speed Difference Direction Difference	Speed Difference Direction Difference
195/2245 GOES E	Speed Difference Direction Difference	- - - - - - - -	Scatter 1 Scatter 2

Images

153/0710	153/1345	153/1410	153/0230	188/1730
NP/TERRA NP/TERRA MAG X2	NP/TERRA NP/TERRA MAG X2	NP/AQUA NP/AQUA MAG X2	SP/AQUA SP/AQUA MAG X2	Meteosat-7

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