%0 Journal Article %A Zhang Xianzhou %A Zhang Yiguang %A Zhou Yunhua %T CLIMATOLOGICAL ESTIMATION OF PHOTOSYNTHE TICALLY ACTIVE QUANTUM VALUE ON QINGHAI XIZANG PLATEAU FROM APRIL TO OCTOBER %D 1997 %R 10.11821/xb199704010 %J Acta Geographica Sinica %P 361-365 %V 52 %N 4 %X Based on the measured data of spectral radiation on Qinghai Xizang Plateau from April to October, 1994, ratio of photosynthetically active radiation ( PAR ) to global radiation was presented, i.e. η =0.439±0.009, and 1J energy of PAR is equivalent to 4.43 μmol quantum. In the climatological estimation of Qinghai Xizang Plateau, following equations can be used to estimate the averages for every ten days of daily total PAR energy HPAR(MJ·m-2d-1)and daily total quantum UPAR(mol·m-2d-1):HPAR=(0.399+0.036lgE*)·H UPAR=(1.768+0.159lgE*)·H H(MJ·m-2d-1) is the average daily global radiation for ten days. E*=E·P0/P,P0(hpa) is the standard atmospheric pressure, P (hpa) is the atmospheric pressure at the spot, E (hpa) is the water vapor pressure on the ground. %U https://www.geog.com.cn/EN/10.11821/xb199704010