##### Comparison with infrared (IR) SST #####

The evaluation is performed for the AMSR2 SST product. 
The AMSR2 SST product data are compared to the Suomi/NPP VIIRS SST product data.
This Suomi/NPP VIIRS SST data is downloaded from JAXA Satellite Monitoring for Environmental Studies homepage (https://www.eorc.jaxa.jp/JASMES/).
We calculate bias and RMSE (Root Mean Square Error) after making Suomi/NPP VIIRS to AMSR2 match-up data.

How to make match-up data is 

Suomi/NPP VIIRS observations with the quality level of acceptable or good are chosen for the comparison. 
Each selected observation is compared with the nearest AMSR2 observation which the footprint center is 
within 325 m (half the VIIRS footprint size) and flagged as normal. 
Observation time gaps are within 15 minutes between AMSR2 and VIIRS. 

If these conditions are satisfied, we calculate the bias and RMSE between VIIRS and average of the nearest AMSR2.


How to calculate bias is 
    diff(i)=AMSR2(i)-VIIRS(i)
    bias=(diff(1)+.......diff(N-1)+diff(N))/N
How to calculate RMSE is  
    RMSE*RMSE=((diff(1)-bias)*(diff(1)-bias)+.......+(diff(N)-bias)*(diff(N)-bias))/(N-1)

The left panels let you choose which sensor and product to check. 
At last if you click Display button, bias and RMSE are plotted for each area.

AREA definition is 
 : 0      All Ocean(-90<=lat<90 0<=lon<360)
 : 1      The Indian Ocean(-40<=lat<40 30<=lon<100)
 : 2      The South Atlantic(-40<=lat<10 -70<=lon<30)
 : 3      The North Atlantic(10<=lat<40 -10<=lon<30)
 : 4      The South-West Pacific(-40<=lat<10 100<=lon<180)
 : 5      The North-West Pacific(10<=lat<40  100<=lon<180)
 : 6      The South-East Pacific(-40<=lat<10 -180<=lon<-70)
 : 7      The North-East Pacific(10<=lat<40 -180<=lon<-100)
 : 8      The North Pole(40<=lat<90 -180<=lon<180)
 : 9      The South Pole (-90<=lat<-40 -180<=lon<180)

The upper left map shows the BIAS and RMSE calculated for each 1.0 x 1.0-degree grid.