We calculeted PAR by Frouin's GLI PAR algorithm using global mapped radiance data.

Monthly PAR (e.g., May 2003) is from daily PAR (e.g., 2003/05/01-31).

1. GLI V2.0 compared with SeaWiFS monthly PAR
1.1 No vical coef

1.2 Using vical coef

• Sea-ice area
• Threshold of solar zenith angle
• Equatorial Pacific

2. Comparison with GMS monthly PAR

Conversion from W/m^2 to Ein/m^2/day
PAR [Ein/m^2/day]=Solar irradiance [W/m^2]*rt
rt=c_vbyl*c_pbye*(24*60*60)/p2mol*(1.-ref)*m2e; (=0.1896)
c_vbyl=0.43;c_pbye=2.77E18;p2mol=6.022E23;ref=0.07;m2ein=1.193;m2e=1.193;

(GMS Solar irradiance (0.05-deg resolution) is Tohoku Univ. SWR monthly data in April 2003)
Kawamura et al., Journal of Oceanography, Vol. 54, pp. 457 to 464. 1998
   

3. Comparison between V2.0 and V2.2 (2003/08/12)
upper (or X-axis): V2.0, lower (or Y-axis): V2.2

• Discontinuity on the 180-deg line

After modifications in treatment of localtime and albedo (2003/04/10),
upper (or X-axis): V2.0, lower (or Y-axis): V2.2

Test of sampling scheme of global radiance data

4. 8-day average PAR using new radiance data and ver.2 & 2.2 algorithms

a) Ver.2.0 v.s. SeaWiFS (1-8 May 2003)

b) Ver.2.2 v.s. SeaWiFS (1-8 May 2003)

(ref, next period 9-16 May 2003)