Analysis of climate conditions on the edge of the Yellow River?
The climate of the Yellow River Basin belongs to the East Asian monsoon zone, the area above Lanzhou belongs to the Tibetan Plateau monsoon zone, and the remaining areas belong to the temperate and subtropical monsoon zones. The seasonal characteristics are that the climate is dry in spring, with lots of wind and sand, and spring drought is prone to occur; in summer, the two Pacific subtropical highs move northward, guiding warm and humid air to enter the Yellow River Basin, intersecting with cold air from the northwest and south, prone to precipitation, and are the cause of heavy rains in the Yellow River Basin. The most common season; in autumn, the western Pacific subtropical high weakens and withdraws southward, and the high-altitude westerly jet stream moves southward, resulting in crisp autumn weather, but there are continuous autumn rains above the Weihe River and Lanzhou, such as the autumn rain in West China; in winter, the western Pacific subtropical high has moved southward and withdrawn, and the Yellow River The northwest air current prevails in the basin, which often causes cold waves, less water vapor, and significantly reduced precipitation.
Due to the vast territory of the Yellow River Basin, numerous mountains, and great height differences between the east and west, the landforms of each region are also very different. At the same time, the basin is located in the mid-latitude zone, and is affected by atmospheric circulation and monsoon circulation in a relatively complex manner. Therefore, the climate of different regions in the basin differs significantly, and climate elements vary greatly from year to season. The basin climate has the following main characteristics.
1. Sufficient sunlight and strong solar radiation
The sunshine conditions in the Yellow River Basin are sufficient in the country. The annual sunshine hours generally reach 2000-3000h. The percentage of oral irradiation is mostly between 50% and 75%, second only to the Qaidam Basin, which has the most sunshine, and is generally about twice as high as that of the Yangtze River Basin south of the Yellow River.
The total solar radiation in the Yellow River Basin is in the middle of the country. The area north of 37' north latitude and the plateau area four to 103' east longitude is 540~670kJ/(cmz·a); In some areas, the radiation is 460-544kJ/(cm'·a). Although it is not as strong as the southwestern part of the country, especially the Qinghai-Tibet Plateau, it is generally higher than the northeastern region and the area south of the Yellow River. It is a strong radiation area in eastern my country.
2. Large seasonal differences and wide temperature differences
The Yellow River Basin has large seasonal differences. According to research by Zhang Jiacheng and others, the river source area above Jiuzhi County in Qinghai Province in the upper reaches has "winter all year round". "; the area from Jiuzhi County to Lanzhou and the middle and upper reaches of the Wei River is "long winter without summer, spring and autumn are connected"; the area from Lanzhou to Longmen is "long winter (six or seven months), short summer (one or two months), and spring and autumn are slightly worse" "; the rest of the basin is "cold in winter, hot in summer, with four distinct seasons."
The wide temperature difference is a major feature of the climate in the Yellow River Basin. The annual average temperature in the Yellow River Basin decreases with increasing height. The annual average temperature is 1-8℃ in the upper reaches, 8-14'C in the middle reaches, and 12-14'C in the lower reaches. In general, along with the three-level terrain step, the temperature changes from cold to warm from west to east, and the east-west gradient of temperature is significantly greater than the north-south gradient.
The annual average temperature is about -4'C, with the lowest center located at the source of the river