The geography and climate of Duchang County
Duchang is located in the subtropical humid monsoon climate zone and is affected by the large water body of Poyang Lake. It is characterized by a mild climate, abundant rainfall, sufficient sunshine, abundant heat, short freezing period, and long frost-free period. Short, summer and winter long. According to meteorological records, the beginning of spring occurs on March 24 on average (the first day when the daily average temperature stably passes 10℃ is the beginning of spring) and lasts for about 65 days. The beginning of summer occurs on May 28 on average (the beginning of summer is the day when the daily average temperature stably passes 22°C) and lasts for about 119 days. The start of autumn occurs on September 24 on average (the day after the last day when the daily average temperature stably passes 22°C is the start of autumn) and lasts for about 59 days. The beginning of winter occurs on November 22 on average (the day after the last day when the daily average temperature stably passes 10℃ is the beginning of winter) and lasts for about 122 days. The turn of winter and spring are often invaded by cold waves, and the weather is changeable and cloudy; the turn of spring and summer is controlled alternately by cold and warm air masses, with continuous plum rains and haze in winter; the turn of summer and autumn is characterized by persistent subtropical high pressure, sunny and hot weather, and drought and little rain. ; In autumn and winter, the cold air from the north invades strongly from the south, causing the temperature to drop sharply and the ground to be frosty.
Temperature: The annual average temperature is 17.1℃, with a range of variation between 16℃ and 17℃. The daily temperature range is 7.1℃. January is the coldest, with an average temperature of 4.4℃, and July is the hottest, with an average temperature of 29.3℃. The order of monthly average values over the years is: 4.4℃, 6.0℃, 10.7℃, 16.5℃, 21.5℃, 25.4℃, 29.3℃, 29.1℃, 24.6℃, 18.9℃, 12.6℃, 6.8℃.
Accumulated temperature: The annual average active accumulated temperature ≥℃ is 5800-6500℃.
Ground temperature: The annual average surface temperature is 19.5℃. 4. Frost-free period and frost-free period: The annual average frost-free period is 261 days, with the longest frost-free period being 300 days and the shortest being 227 days. The annual average frost-free period is 271 days, with the longest being 300 days and the shortest being 239 days.
Sunshine: The average annual sunshine hours are 2076.3 hours, and the sunshine rate is 47%.
Precipitation: The annual precipitation from 1952 to 1958 was 1728.28 mm, and the average annual precipitation from 1959 to 1989 was 1391.5 mm.
Evaporation and dryness: The annual average evaporation is 1572.5 mm. The annual average evaporation is greater than the precipitation, the relative humidity is 78%, and the dryness is 1.27.
Disastrous weather: The main disastrous weather and natural disasters include spring cold, Xiaomanhan, wind and hail, plum rain, autumn drought, rotten autumn, cold dew and wind; floods, droughts, wind and hail, and pest and disease disasters. Other disasters, such as low-temperature freezing snow disasters, plagues, earthquakes, etc., generally occur less frequently, have smaller disaster areas, and cause lighter losses.