Page 88 - Design of Solar Thermal Power Plants

2.5 DISTRIBUTION OF THE SOLAR RESOURCE IN SEVERAL 77

resources; Guizhou is within the East Asia monsoon region while being
influenced by westerly and subtropical circulation systems. It also has a
frequent and intensive airflow intersection from the north and south. In
such a specific geographic location and natural environment, which ex-
periences the impacts of solar radiation and atmospheric circulation, the
unique climatic characteristics of Guizhou are formed, namely tempera-
ture and humid weather and an obvious three-dimensional climate;
distinctive seasons; a long frost-free period; no intensive thermal energy
during summer and no severe cold in winter; abundant thermal energy,
extreme as well as mild cold weather; sufficient precipitation; frequent
drought and flood; weak global radiation with widely scattered sunshine;
more rain and less sunshine; lower wind speed; and a variety of
frequently occurring disasters.
In most areas of Guizhou, the annual mean temperature is 14e18 C,

the accumulated temperature over 10 C is 3500e5500 C, and the frost-

free period is 260e330 days. During winter months, the mean tempera-
ture is 4e9 C, and the extreme minimum temperature is 5to7 C;

whereas during summer months, the mean temperature is 20e25 C, and

the extreme maximum temperature is 32e36 C. Annual precipitation falls
in a range of 1100e1300 mm, which is nearly double the amount for the
North China Plain. During the summer half-year, the temperature in
Guizhou is comparatively high with concentrated precipitation, sufficient
sunshine as well as thermal, water, and light synchronization.
2.5.6.2 Solar Radiation of Guizhou
Influenced by a stationary front, Guizhou features numerous rainy
days, significant cloud cover, great cloud thickness, and a low amount of
global solar radiation reaching the ground; in most areas, global annual
2
radiation falls in a range of 3349e4186 MJ/m ; it is a region with minimal
solar global radiation. Scattered radiation in Guizhou accounts for an
especially large proportion of global radiation, with Zunyi and Guiyang
both having over 60% scattered radiation; Xianning, with more clear days,
has a scattered radiation proportion above 50%. Especially in winter, the
proportion of scattered radiation exceeds 67%; in specific years, global
radiation may consist almost entirely of scattered radiation.

2.5.7 The Solar Resource in Hainan

Hainan is located north of the South China Sea south of 20 N; the

Qiongzhou Strait facing the mainland is just 20e30 km across the sea.
Being within a tropical climate region, Hainan is not only greatly influ-
enced by the mainland but also significantly regulated by the ocean;
atmosphereeocean thermal and water exchange as well as seasonal var-
iations have direct impacts on temperature and precipitation in Hainan.