Geographical environment of Langfang

Langfang City is located in the mid-latitude zone, with a continental monsoon climate of warm temperate zone and four distinct seasons. Summer is hot and rainy, winter is cold and dry, spring is dry and windy, and autumn is refreshing and cool. Sufficient light and heat resources, rain and heat in the same season, are conducive to crop growth. At the same time, however, there are many meteorological disasters, such as dry-hot wind, thunderstorm, hail and strong wind, continuous rain and cold wave, which often have adverse effects on agricultural production.

Temperature: annual average temperature in Langfang (197 1-2000)1.9℃. January is the coldest, with an average monthly temperature of -4.7℃. July is the hottest, with an average monthly temperature of 26.2℃.

Frost-free period: the first frost in Langfang generally begins in the middle and late days of 10/0, and the last frost generally ends in the middle and late days of April of the following year, with an average frost-free period of about 183 days.

Precipitation: The average annual precipitation in Langfang (197 1-2000) is 554.9 mm ... The seasonal distribution of precipitation is uneven, mostly concentrated in summer, and the precipitation from June to August can generally reach 70-80% of the total annual precipitation.

Sunshine: The average sunshine hours in Langfang (197 1-2000) are about 2660 hours, with the most sunshine hours in May and June each year.

Wind power: Langfang has a continental monsoon climate, with northerly winds in winter and southerly winds in summer, with an average annual wind speed of 1.5-2.5 meters. Most of Langfang city is located in the depressed area. With the subsidence of the earth's crust, the ground is gradually filled with Quaternary sediments, which leads to a large subsidence thickness of Cenozoic strata. The terrain of the whole city is relatively flat and monotonous, generally 2.5-30m above sea level, with an average elevation of about13m. Due to floods, alluvial action, repeated crevasse siltation of rivers, staggered distribution of sediments, and the influence of wind and human activities, the landforms in the territory are quite different, with gentle hills, depressions, sand dunes and small alluvial piles everywhere, and the appearance of the city is large and flat.

The terrain in the northern region is relatively high, high in the north and low in the south, and there are many types of landforms. There is a small piece of low hills in the northeast corner of Sanhe County, which is the remnant vein on the south side of Yanshan Mountain, covering an area of 76 square kilometers. Generally, the mountain height is 200-300 meters above sea level, and the mountain behind Daling is 52 1 meter above sea level, which is the highest peak in the city. Followed by Longmen Mountain, 459 meters above sea level; There are mountainous hills in the west and south, along the southern foot of Yanshan Mountain, and the piedmont plain is distributed in an east-west belt with an area of 773 square kilometers. The terrain inclines from north to south, with an altitude of 10 to 30m, with an average altitude of about18m. Further south, the south-central part of Xianghe County is an alluvial plain with a slope of 1/3000, an elevation of 5-16m, and an average elevation of 1 1 m..

The central and southern parts of Langfang are all alluvial plains with flat and single landform types, with a total area of 5 1.79 square kilometers, accounting for more than 80% of the city's total area. 2.5-25m above sea level, slope1/2500-110000. The terrain north of Daqing River is low from northwest to southeast, and the terrain south of Daqing River is low from west to northeast. The famous Wen 'anwa and Dongdian are located in the north and south of Daqing River, with a total area of 79,000 hectares, accounting for 12.3% of the city's total area. Among them, Wen 'anwa covers an area of 59,000 hectares, with an average elevation of less than 4 meters, and the area north of Mawuying Village is only 2 meters above sea level, which is the lowest point in the city. Dongdian Lake covers an area of 20,000 hectares, with an average elevation of about 5 meters and the lowest point of 2.5 meters.

The topography of the whole city gradually inclines from north, west and south to the lower reaches of Haihe River in Tianjin.