From February 25th to 27th, there was a large range of rain and snow in the winter wheat area in the north. Compared with the two precipitation processes from February 9th to 10th and 12th to 13th, the precipitation process was wider. The process has a large amount of precipitation and a long duration. The cumulative precipitation in most areas of northern winter wheat and drought-affected areas exceeds 10 mm. The precipitation in southeastern Shaanxi, south-central Henan, southern Shandong and the peninsula, northern Anhui, and northern Jiangsu reaches 20-40. Millimeter. In most of the northern winter wheat, the soil moisture in the arid areas was significantly improved, and the drought in some areas was alleviated. The meteorological department seized the favorable weather conditions and organized large-scale aircraft and ground artificial precipitation (snow) operations, adding about 1.47 billion tons of water to the dry areas.
It is estimated that on February 28, there will be 1 to 5 mm of rainfall in the southwestern part of Shaanxi, central and southern Henan, and central and northern Susong. The rainfall process will be weakened at night on the 28th.
From February 28 to March 1, the temperature in the Huanghuai dry area of â€‹â€‹North China is relatively low and it is not suitable for irrigation. It is suggested that the winter wheat and arid areas should pay close attention to the weather changes. The areas where the drought has not eased will catch the spring irrigation in the early March when the temperature rises in the first half of the year. In the early stage, the drought will be heavier than the heavy field, and it is necessary to do the field management in the greening period, re-apply the body fat and promote the seedlings. The situation turned better.
Large-scale precipitation in the winter wheat area in the north
From February 25th to 27th, there were large-scale rain and snow weather in the northern winter wheat drought area. The cumulative precipitation in most parts of Shaanxi, most of Shanxi, most of Hebei, Henan, Shandong, central and northern Anhui, and northern Jiangsu has 5-15. In millimeters, precipitation in some areas is 20 to 49 mm (Fig. 1). At 08:00 on the 27th, the depth of snow in central and northern Shaanxi and most parts of northern China was 1 to 5 cm. The depth of snow in central Shaanxi, southwestern Shanxi, southern Hebei, southern Tianjin, and northern Shandong was 6-10 cm.
Compared with the two precipitation processes from February 9 to 10 and from 12 to 13, the precipitation process has the characteristics of long duration, wide coverage and large process precipitation.
Long duration: The duration of the precipitation will last up to 4 days, and the number of precipitation days will be 2 days longer than the last two rain days.
Wide coverage: The precipitation covers all drought-affected areas in northern winter wheat. The precipitation coverage area above 10 mm is about 800,000 square kilometers, and the precipitation coverage above 25 mm is about 150,000 square kilometers.
Process precipitation: large-scale precipitation in southeastern Shaanxi, south-central Henan, southern Shandong and the peninsula, northern Anhui, northern Jiangsu, 20-35 mm, Anhui Wuzhou fence (49 mm), Suzhou demonstration park (44 mm), Henan Xixian (41 mm) precipitation exceeds 40 mm.
Most of the drought in the northern winter wheat area has been effectively alleviated, which is very beneficial to the growth of winter wheat.
(1) Precipitation in the northern winter wheat area is effectively replenished
From October 1, 2010 to February 25, 2011, the cumulative precipitation in most of North China, Huanghuai, and Jianghuai is generally less than 50 mm. Compared with the same period of the previous year, precipitation in most of southern China, Huanghuai and Jianghuai is generally biased. Less than 5 to 80%, of which most of Shandong, southern Hebei, central and eastern Henan, northern Anhui, and northern Jiangsu are 80% less. After the precipitation from the 25th to the 27th, the precipitation in the northern winter wheat area has changed significantly. The cumulative precipitation in most areas is more than 30% less than normal, and there is no more than 80%.
(II) Significant improvement of soil moisture in the affected areas of northern winter wheat
The comparison of soil moisture monitoring on February 25 and 27 showed that due to the influence of precipitation, the soil moisture in the northern winter wheat arid area has been significantly improved, and the area of â€‹â€‹the missing area has been reduced. Only parts of southeastern Hebei and western Henan are 0. In the absence of 10 cm soil, the 10 cm soil defect in the northwestern part of Anhui will also be further improved with the gradual infiltration of precipitation. Shallow soil moisture is abundant in parts of eastern Henan and southern Shandong.
The precipitation process has effectively alleviated the drought in the northern winter wheat area. The drought in the southwestern part of the mountain, the northern and eastern parts of Henan, the majority of Shandong, and the northern part of Anhui have eased, which is beneficial to the improvement of winter wheat seedlings and greening.
In March, the winter wheat in the north is slightly higher in the drought-stricken areas, and most of the precipitation in the dry areas is close to normal or less, and it is still necessary to prevent the repeated development of drought.
(1) There will be weak precipitation in the northeast winter wheat drought area in the next ten days.
On February 28, there were 1 to 5 mm of rainfall in the southwestern part of Shaanxi, central and southern Henan, and central and northern Susong. The rainfall process will be weakened at night on the 28th. From February 28 to March 1, the minimum temperature in northwestern Shaanxi and northern North China can drop from minus 10 Â°C to minus 6 Â°C. The lowest temperature in central and southern China is between minus 6 Â°C and minus 3 Â°C. The lowest temperature in the north-central part of Huanghuai is minus 4 Â°C. To 2Â°C below zero, the lowest temperature in the southern part of Huanghuai is minus 2Â°C to 0Â°C, and the lowest temperature in Huaihe is about 0Â°C.
On March 5, there was a weak precipitation process in southern Henan and northern Susong, and the precipitation was generally 1 to 5 mm.
(2) In March, the winter wheat in the north is slightly higher in the drought-stricken areas, and most of the dry areas are near normal or less.
In March, the temperature in the winter wheat area in northern China was slightly higher than that in normal years. The precipitation in central and northern Hebei is 1~10 mm, and the precipitation in most parts of Shanxi, southern Hebei, northern Henan, and most of Shandong is 10-25 mm. The precipitation in most parts of Henan, southern Shandong, northern Anhui, and northern Jiangsu has 25-50. In millimeters, the precipitation in central Anhui and central Jiangsu is 50-100 mm. Compared with the same period of the previous year, except for most of Shanxi, western Hebei, and northwestern Henan, the precipitation is slightly more than normal. The precipitation in the rest of North China and Huanghuai is close to normal or less. Meteorological drought in Henan, southwestern Shanxi, and Anhui may be alleviated, and meteorological drought in northern Shandong and northern Jiangsu may continue or develop.
Concerns and suggestions
At present, the winter wheat in the north will gradually enter the greening period. The local areas should be managed according to the conditions of the seedlings and the lyrics. The areas with no drought relief should grasp the spring irrigation in the early March when the temperature rises in the first half of the year. Re-apply the body fat, and promote the improvement of the seedlings. From February 28 to March 1, the average daily temperature in North China, Huanghuai and other places will drop below 3 Â°C, and it is not suitable for irrigation.
In addition, precipitation in the eastern part of the northwestern region, most of North China, and Huanghuai in March is close to normal or less. As the temperature rises and the water requirement for winter wheat greening increases, all localities should continue to pay attention to the changes in soil moisture in the winter wheat area. Take measures such as irrigation to prevent the drought from developing again.
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