Since October 2010, the precipitation in most of North China, Huanghuai and Jianghuai has been decreasing. The average precipitation in Hebei, Shanxi, Shandong, Henan, Jiangsu and Anhui provinces is the second lowest in the same period since 1961. The number of long continuous no precipitation days was the third highest in the same period since 1961. As of January 13th, the western and southern parts of Shandong, most of Henan and other places were moderate to heavy, and the central and eastern parts of Henan and parts of Shandong were drought. The areas with poor irrigation conditions in the southern part of Huanghuai and the northern part of the Yangtze River are more severely affected by drought, and the seedlings are deviated from the same period of the previous year. The main cause of the meteorological drought in North China and Huanghuai is that the cold air force has been strong since October last year, and the western Pacific subtropical high is obviously weak. The water vapor from the Pacific Ocean is difficult to transport to the north of the Yangtze River.
It is expected that the rain and snow in most parts of the north will remain less in the next ten days. The drought in southern Hebei, most of Henan, parts of western and central Shandong, and northwestern Anhui continue. After the winter solstice and early spring, the precipitation in North China and Huanghuai is less than normal, and the meteorological drought may continue to develop. To this end, it is recommended that all localities strengthen field management according to crop conditions and do a good job in drought relief.
I. Current drought conditions in Huanghuai and other places in North China and their main impacts
(1) Huanghuai in North China has less precipitation, no precipitation time, and continuous development of meteorological drought
The amount of precipitation is significantly less, and there is no longer precipitation. Since October last year (October 1, 2010 to January 13, 2011), precipitation in most of North China and Huanghuai and Jianghuai is generally below 50 mm, less than 10 mm in most parts of Shandong, southern Hebei, and northern Henan. Compared with the same period of the previous year, the precipitation in the central and southern parts of North China, Huanghuai and Jianghuai is less than 5 to 90%. The average precipitation in Hebei, Shanxi, Shandong, Henan, Jiangsu and Anhui provinces is only 40.2 mm, which is 53% less than normal. It is the second lowest in the same period since 1961, second only to 1970, including precipitation in Henan and Shandong. The quantities are the minimum and minor values ​​of the historical period. Since November 2010, precipitation in Beijing and Tianjin has been scarce, and precipitation has been the lowest in the history since 1961.
Since October 2010, the average longest continuous no precipitation days in the six provinces reached 45 days, 14 days more than normal, second only to 1974 and 1989, the third highest in the same period since 1961; Beijing (80 days) ), Tianjin (64 days), Shandong (50 days), Shanxi (60 days), the longest continuous no precipitation days are the same in history, Henan (49 days) is the third, Hebei (51 days) is the fourth many. The longest continuous no-precipitation days of 43 stations in North China, Huanghuai and Jianghuai reached the extreme event monitoring standards. Among them, there were 4 stations in Shandong with super historical extremes, and Shandong Rushan and Haiyang respectively reached 60 days and 85 days.
The meteorological drought in some areas of North China and Huanghuai has a long duration and a heavy degree in some areas. Since October 2010, meteorological drought has developed rapidly in most areas of Huanghuai, Jianghuai and the eastern part of the Northwest. At present, moderate meteorological droughts are concentrated in southern North China, Huanghuai, and northwestern Jianghuai. Among them, the western and southern parts of Shandong, most of Henan and other places are moderate to heavy, and the central and eastern parts of Henan and Shandong are particularly dry. As of January 13, the meteorological drought in most parts of Huanghuai and southern China has a duration of 30 to 60 days, and some areas of Huanghuai have reached 60 to 90 days.
(2) The soil surface in the dry area is poor, and the cultivated layer is still sensible.
The lack of precipitation led to a decline in soil moisture. The soil moisture monitoring results on January 8 showed that the relative humidity of 10 cm soil in the south of Hebei, most of Henan, the south of the mountain, and the northwest of Anhui was below 60%, partially below 40%. The soil surface is poor, but the soil moisture of 20 cm in most areas is better. The relative humidity of the soil is only below 60% in the northwest and south of Henan, the northwest of the mountain, and the northwestern part of Anhui.
(3) Winter wheat in southern Huanghuai and northern Jianghuai is affected by drought
Due to the abundant precipitation in most of the winter wheat areas in China from August to September 2010, the soil bottom was effectively increased, and winter irrigation was carried out in most areas. The farmland soils in the north of China and Huanghuai were frozen in the middle and late December, and the western part of Huanghuai was frozen from north to south in the first half of January. The loss of soil water was reduced, and the winter wheat was in the wintering stage, the water demand was small, and the meteorological drought was already wet in winter. Winter wheat has no significant effect. The areas with poor irrigation conditions in the southern part of Huanghuai and northern Jianghuai are affected by drought, and the seedlings are deviated from the same period of the previous year. Since the beginning of this year, temperatures in dry areas have generally been 2 to 4 °C lower than normal, and drought has increased the risk of freezing damage to crops.
Second, the cold air is strong and the water vapor transport conditions are poor.
The main reason for the occurrence of meteorological drought due to less precipitation in most of North China and Huanghuai is that the cold air force is strong since October 2010 and the southern water vapor transport conditions are poor. Since July last year, the rapid development of the La Niña event has had a significant impact on the atmospheric circulation. From the autumn, the global tropical and subtropical atmospheric circulation has been significantly adjusted. The western Pacific subtropical high has been significantly weakened, making it difficult for water vapor from the Pacific to be transported to the north of the Yangtze River. After the La Nina incident, this year's mid-high latitude atmospheric circulation anomaly maintained the meridional characteristics for a long time, which made the northerly airflow in the eastern part of China strengthen, guiding the middle and high latitude cold air to the south, and the intersection of cold and warm airflow is difficult to appear in the area north of the Yangtze River. In North China, Huanghuai and other places, there is a lack of effective precipitation and meteorological drought.
3. Meteorological drought will continue in the late winter to early spring
(1) Weather trends in the next 10 days
In the next 10 days, the cold air activities affecting China are more frequent. The temperature in most parts of the country is 1~2°C lower than normal. The rain and snow in most parts of the north are less. The low temperature and drought continue to the south of Hebei, most of Henan, and Shandong. Winter wheat, which has not been winter-fed in parts of the western and central parts of China, and northwestern Anhui, poses a threat to winter.
(2) Meteorological drought in the Huanghuai area of ​​North China will continue to develop in the early winter and early spring
It is expected that after the winter solstice (January to March), precipitation in North China and Huanghuai will be less than normal, and meteorological drought will continue to develop. In April, the precipitation is close to the same period of the year. The precipitation in North China is 10 to 25 mm, and the precipitation in Huanghuai is 25 to 50 mm. The meteorological drought will be relieved.
Fourth, attention and recommendations
At present, winter wheat is still in the wintering period, and planting vegetables is in the key growth stage of pre-holiday listing. For the current drought and future development trends, it is recommended that:
First, the winter wheat area needs to be warmed up during the winter wheat wintering period. It can be covered with organic fertilizer, grass wood fertilizer or crushed straw to warm and protect the roots, promote root growth, reduce the wintering rate of wheat seedlings, and ensure the winter wheat safely. .
Second, facility agriculture needs to take measures such as strengthening wind, warming and warming according to the weather forecast, so as to avoid or reduce the adverse effects caused by high wind and low temperature.
Third, the dry areas need to seize favorable weather, implement artificial precipitation and snow increase operations, and mitigate and mitigate the impact of drought on agricultural production and forest fire safety.
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