How Do I Predict the Weather?

Climate forecast, also known as climate forecast or climate outlook. Outlook on the future climate of a region. In China, it usually refers to the ultra-long-term forecast with a forecast period of more than one year. Use the law of climate evolution to make inferences about climatic conditions in the years and even decades or longer. Its main basis is long-term climate records, solar activity, geomagnetism, sea ice, tree rings, historical records, and archeological materials. In addition, it also considers the impact of human activities.

Climate forecast, also known as

Climatological forecasting is different from climate forecasting. The former is a forecasting method and the latter is a forecasting form.

Climatological forecasting is a method of making forecasts based on climate evolution. Generally, after grasping the climatic data of a certain area or a place for many years, the average value of relevant elements, frequency charts and other data can be obtained statistically. When forecasting, the climate value of the corresponding period is taken as the value of the future weather elements. Because this method can not take into account the short-term characteristics of atmospheric circulation, it can be used for weather forecasting in areas with long timeliness, lack of real-time data, or low latitudes. Forecast results are generally used only as a reference for climate background. ^[1]

At present, most stations in China compile weather forecasts based on the evolution of the climatic sequence itself and methods related to factors.

Extension of climate data

Long-term data are needed to make climate forecasts. According to the scale theory, the ratio of forecast timeliness to data length is 1:10. In order to make up for the lack of modern instrumental data, in 1974-1978, the Meteorological Science Research Institute of the Central Meteorological Bureau, in addition to extending the precipitation in Beijing to 250 years, according to the records of the National Palace Museum Beijing "Rain and Rain", also twice with Beijing University, Nanjing University jointly organized the meteorological departments of all provinces (cities, districts), in collaboration with the Long-term Hydrographic Office, the Institute of Geography, Chinese Academy of Sciences, and the Institute of Geography of Jiangsu! "Annual Drought and Flood Distribution Map", this is China's first large-scale, systematic and numerical drought and flood data. In order to study the climate change trend in western China, where historical records are scarce, the Institute of Geography of the Chinese Academy of Sciences went deep into southern Tibet and collected a large number of tree ring specimens. The Meteorological Science Research Institute of the Central Meteorological Bureau organized the meteorological departments of the nine provinces (regions) in the southwest and northwest to carry out annual ring climatology research, and cooperated with the Shaanxi Meteorological Bureau, Lanzhou Glacier and Frozen Soil Research Institute, and Lanzhou University on the south side of Tailing A number of tree ring specimens were collected from the Numabei Plateau and the Qilian Mountains. The trees are up to 935 years old. This is the longest annual ring collected in China and can reflect China's climate change. It provides a more objective basis for studying the climate change in China for nearly a thousand years and making climate forecasts.

Climate Forecast Phase Analysis

Climate change has obvious stages. Not only are the average values significantly different at each stage, but other climate characteristics and forecast indicators are also different. In fact, the phase can be regarded as a phase in the climate cycle. It is the basic period of the climatic process, but the phase in each longer climate cycle is composed of several shorter cycles. Because climate change has different scale cycles, there are also stages of different lengths. How to grasp the stages and their transitions is an important research topic of current climate forecasting.

At present, in this regard, objective criteria for dividing wet and dry periods and cold and warm periods have been proposed. Attempts have also been made to use mathematical statistics to divide the stages. Some have also proposed the idea of dividing stages by comprehensively considering various climatic factors, including circulation characteristics. This is a feature of China's climate forecasting methods.

Crowd Forecasting Experience

Xu Guishan, a veteran farmer in Yitong County, Jilin Province, has accumulated more than 50 years of experience in forecasting apologetic years. It is pointed out that the abundance of apologies has a 6-7 year cycle. That is to say, the bumper year lasts for 3-4 years, followed by a flood year or disaster year, then a dry or heavy drought year, and finally a rainy year. Thus forming a complete cycle. Chen Jingcheng, an old farmer in Shishou County, Hubei Province, has recorded the planet's position, early waterlogging, and the Yangtze River water level for 40 years. He found that if several planets move unevenly in the same year, there will be floods if several planets are concentrated near the summer solstice . In recent years, many stations have learnt and summarized the experience of the farmers watching the sky, extending the time limit. Practice has proved that there are a lot of clues to weather forecasting in the masses' experience.

Climate forecast solar activity

The relationship between climate change and solar activity is mainly manifested in the relationship between climate elements and different time scale periods and phases of solar activity. With the extension of China's climate data, it is also found that China's climate is not only related to the 11-year and 22-year cycles of solar activity, but also to the century cycle of 80-90 years and the bicentury cycle of 170-200 years. Recently, more attention has been paid to the relationship between the solar active Mundell minimum (1645-1715), the Spall minimum (1460-1550), and the medieval maximum (1100-1250) with China's climate.

The effectiveness of meteorological forecasting based on Xunzi is not only manifested in the closeness and stability of the correlation between climate change and solar activity changes, but also related to the stability of the sunspot cycle itself and the reliability of sunspot forecasts. The recent discussion of Mundell's minima involves the stability of the mule cycle and the equivalent of the mule forecast.

Weather forecast astronomical factor

The use of moon shadows to forecast droughts and floods has a long history in China, and we can make drought and flood forecasts for more than one year based on the changes in the daily declination. Many weather phenomena are related to the phases of the moon. Some significant cycles in climate, such as 19 and 36 years, are consistent with astronomical cycles (Astronomical and Meteorological Symposium, 1979). The frequency of planetary influx, solar and solar eclipses, droughts and floods, and coastal cooling all have certain relationships. The change of the warm and cold period in China's history is related to the converging cycle of the nine planets in 178.7 years.

Climate forecast atmospheric circulation

The secular variation of the circulation is the direct cause of climate change. Peking University has drawn a set of global sea level atmospheric pressure maps from 1.4.7 to October since 1871, and studied the relationship between atmospheric circulation vibration and climate vibration in China in the past century. Many units use changes in atmospheric activity centers to predict droughts, floods, and cold and warm conditions in the region. Since 1891, the secular variation of the daily circulation pattern of 500 mbar in the northern hemisphere has been closely related to typhoon activity in the Western Pacific and the annual maximum water level of the Yangtze River in Hankou. According to the multi-year evolution of the circulation pattern and its relationship with solar activity, the future development of the circulation pattern can be predicted. The study also found that there is a correlation between the large-scale temperature changes in China and the meridional index with a five-year lag.

Climate forecast ocean change

Both the activities of the subtropical high that affect summer precipitation in China and the tropical sea temperature have periodic oscillations of about three years, and the changes in the subtropical high are behind the changes in sea temperature in the first two quarters. The morning and evening when the Yangtze River reaches Mei, the amount of Meiyu and the length of Meiyu are not only related to the sea temperature in the early Kuroshio area, but also to the coastal sea temperature in Peru in winter. The well-known El Niño phenomenon is a vibration system in which the ocean currents, upwelling currents, sea temperature, and atmospheric circulation interact in the eastern equatorial Pacific Ocean, which has a period of about 6 years. The Gulf Stream is the most influential ocean current in the northern hemisphere. It not only directly affects the European climate, but also connects with China s summer drought and floods through a transmission process, which takes about 1 to 2 years.

Geophysical factors for climate forecast

The Institute of Geography, Chinese Academy of Sciences has studied the effects of changes in the earth's rotation speed and polar movement on precipitation in the middle and lower reaches of the Yangtze River and northern China during the flood season, Asia-Europe meridional circulation index, Pacific subtropical high, and annual mean flow in Hankou. The overall amplitude of the pole movement is 6-7 years. The Earth's rotation speed has periods of 89.60.30.22 and 11 years.

Climate forecast of Tibetan Plateau thermal conditions, geothermal temperatures at different depths

The Qinghai-Tibet Plateau has an impact on the weather in the eastern part of China, both in terms of power and heat. The large-scale snow cover and ground temperature changes that reflect the thermal conditions of the underlying surface vary greatly from year to year. Abnormal snow will strengthen the cold source of the plateau in winter. The change of underground heat is also an important factor affecting the ultra-long-term weather changes. The change period of deep ground temperature below 3.2 meters is more than one year.

Method for statistical analysis of climate forecast

In terms of statistical analysis methods, in addition to the time series analysis method commonly used in long-term forecasting, Mo Zongsheng also proposed a statistical climatology method to study the discrete series of binary variables for the problem of early waterlogging forecasting. Calculation formula of the cycle. In data processing, in addition to the commonly used moving average, low-pass filtering is used to eliminate the effects of short periods in the sequence. The Gansu Meteorological Research Institute has designed a set of filters to study the evolution of various vibration components of the original sequence in time series. ^[2]