Page 79 - Design of Solar Thermal Power Plants

2.5 DISTRIBUTION OF THE SOLAR RESOURCE IN SEVERAL 69

2.5.2 The Solar Resource in Lhasa
The capital of the Tibet Autonomous Region, Lhasa is located slightly
southeast of the middle of Tibet; it stands on the midstream valley plain of
the Lhasa River branch of the Yarlung Zangbo River, enjoying a plateau
temperate zone with a semiarid monsoon climate. Its coordinates are
91 08 E and 29 40 N with an elevation of 3658 m. It is a plateau arid-
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climate region featuring strong radiation, comparatively low tempera-
tures, moderate precipitation, and thin air; the sunshine duration here is
over 3000 h, giving the city the nickname “Solar City.” In summer, the
temperature is not high. Arid seasons can be clearly distinguished from
wet. The rainy season, which exhibits a tight precipitation period, consists
mainly of days with clear daytime skies and rainy nights.
2.5.2.1 Weather Conditions in Lhasa [7]
Lhasa has a high elevation that results in thin air as well as compara-
tively low temperatures that vary greatly between day and night. The

mean temperature in June is 15.9 C, while the mean maximum is 23.2 C;

it has the year’s highest temperature. In January the mean temperature

is 1.6 C, while the mean minimum is 9.1 C; it has the year’s lowest

temperature. The multiyear extreme maximum temperature is 29.9 C,

and the extreme minimum temperature is 16 C, which respectively
appeared during June and January (refer to Table 2.6).
2.5.2.2 Solar Radiation and Sunshine Duration of Lhasa
Lhasa is located within the QinghaieTibet Plateau temperate zone
semiarid monsoon climate region, enjoying annual sunshine duration of
3000 h and featuring arid and windy weather in winter and spring; the
annual frost-free period for the area lasts only 100e120 days. The annual
precipitation is 200e510 mm and concentrated in JuneeSeptember with
frequent night rains. Relatively speaking, during MarcheOctober the
weather is warm and humid. From 1961 to 1970, the annual mean sun-
shine duration was 3005.7 h, and the sunshine percentage was 68%; there
are 108.5 clear and 98.8 overcast days on average for the year, and annual
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global solar radiation is 6680e8400 MJ/m (refer to Table 2.7).

2.5.3 The Solar Resource in Golmud
Golmud is located in the hinterland of the QinghaieTibet Plateau south
of the boundary of the Haixi Mongol and Tibetan Autonomous Prefec-
ture. The area consists of the Qaidam Basin Midsouth Area and the
Tanggula Mountains that have not been mutually connected, with co-
ordinates of 35 10 e37 45 N and 90 45 e95 46 E with a total area of
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about 8.1 10 km . The urban area is located on the alluvial plain of the