State of China’s climate in 2019

ZENG Hongling,XIAO Chan,CHEN Xianyan,CHEN Yu and YE Dianxiu

National Climate Center,China Meteorological Administration,Beijing,China

ABSTRACT

KEYWORDS Climate state;meteorological disasters;weather and climate events;2019

1. Temperature

According to the World Meteorological Organization Statement on the State of the Climate in 2019, the global average temperature of 2019 was 1.1°C above the pre-industrial average, which is the second warmest on record. China also experienced a warm year.The mean temperature in China in 2019 was 10.34°C,which was 0.79°C above normal, and the year 2019 was the fifth warmest year since 1951 (Figure 1(a)). In terms of spatial distribution, temperatures across almost all of China were above normal, with anomalies of 1-2°C in most of Northeast China, southeastern North China, most of Huanghuai, eastern Inner Mongolia, northeastern Xinjiang, eastern Yunnan,southern Sichuan, and Hainan (Figure 1(b)).

In terms of the seasonal cycle,the four seasons were all warmer than normal in China and the seasonal mean temperature anomalies for winter (December 2018 to February 2019), spring (March to May), summer (June to August),and autumn(September to November)were 0.2°C,1.1°C, 0.5°C, and 1.0°C, respectively. Furthermore, the temperature in autumn was 11.0°C,ranking the third highest since 1951.

In terms of monthly mean temperature,all 12 months were warmer than normal, but especially April, which was the second warmest April since 1951, with an anomaly of 1.8°C.

In 2019, extreme high-temperature events occurred more often than normal. In terms of the daily maximum temperature,348 stations reached the extreme event standard,among which 64 stations recorded their highest daily maximum temperature.Meanwhile,extreme cold events in China were less frequent than normal in 2019.In terms of daily minimum temperature, only 22 stations reached the extreme event standard,and Nyalam in Tibet recorded its lowest daily minimum temperature (?21.7°C, on 29 January)since meteorological observations began.

2. Precipitation

The total rainfall in China in 2019 was 645.5 mm, which was 2.5% above normal and 4.2% below that in 2018(Figure 2(a)). The year 2019 was the eighth consecutive wet year since 2012.The rainfall anomaly pattern showed that most of northern China was generally wet,whereas the precipitation in southern China was close to or less than normal.The areas with an annual rainfall amount that was 20%-100% more than normal included central and northern Northeast China,central and eastern Northwest China, western Inner Mongolia, southwestern Xinjiang,western Tibet, northern Sichuan, and eastern Zhejiang.However, the rainfall was 20%-50% below normal over central and western Huanghuai, most of Jianghuai and Jianghan, central and southern Yunnan, and eastern Xinjiang. The rainfall in 2019 was close to normal over most other areas of China(Figure 2(b)).

Figure 1. (a) Annual mean temperature in China during 1951-2019 (units: °C), and (b) anomalies in 2019 (units: °C, relative to the 1981-2010 average).

At the provincial scale, 17 provinces (including autonomous regions and municipalities) exhibited higher than normal annual precipitation.Of these provinces,Heilongjiang experienced its wettest year since 1961. However, the precipitation in the 14 other provinces was less than normal,and Henan was the second driest since 1961.

Figure 2. (a) Total annual rainfall in China during 1951-2019 (units: mm), and (b) anomalies for 2019 (units: %, relative to the 1981-2010 average).

In the six administrative regions of China, annual precipitation was above normal in Northeast China,Northwest China, and South China, whereas it was below normal in North China, the middle and lower reaches of the Yangtze River, and Southwest China. In the seven river basins, annual precipitation was near or above normal except in the Huaihe River Basin and Haihe River Basin. Songhua River Basin experienced its wettest year since 1961, with annual rainfall 32% more than normal.

For the four seasons, winter, spring, and summer were wet whereas autumn was dry. The rainfall total in winter was 55.8 mm,which was 36%more than normal and ranked as the fourth wettest winter since 1961. In particular,the middle and lower reaches of the Yangtze River and Southwest China experienced total rainfall amounts that were 65% and 40% more than normal,respectively.The rainfall amounts in spring and summer were both 4% more than normal. However, in autumn,the rainfall total was 112.6 mm,which was 6%less than normal,especially in the middle and lower reaches of the Yangtze River and South China, where the rainfall total was 40%and 37%less than normal,respectively.

The annual mean number of rainy days (daily precipitation greater than or equal to 0.1 mm) in China in 2019 was 101.7 d,which was 1.4 d less than normal.For heavy rain in 2019, the number of days when stations recorded a daily rainfall total greater than or equal to 50 mm was 6354, which was 6.4% more than normal.Heavy rain days were close to normal across most of China,with 3-5 d more in the local areas of northeastern Heilongjiang, eastern Zhejiang, northern Fujian, central Jiangxi,and southern Hunan.

The seasonal march of the rainy season is an important aspect of climate system evolution in China. The main characteristics of the rainy season are shown in Table 1. The first rainy season in South China in 2019 started earlier and ended later, with the longest rainy period since 1961 and abundant precipitation. The onset and end of the rainy season in Southwest China were both later than normal, with decreased precipitation. The mei-yu season started later and ended earlier, with decreased precipitation.The rainy season in North China started later and ended close to normal, with decreased rainfall. The onset and end of the rainy season in Northeast China started earlier and ended later, with increased rainfall.The autumn rain in West China started earlier and ended later, with increased rainfall.

The number of extreme precipitation events in China in 2019 was close to normal. There were 225 stations with daily precipitation reaching the extreme event standard,among which 54 stations recorded their maximum daily precipitation.In addition,49 stations recorded their maximum daily continuous precipitation, and 52 stations recorded their longest durations of continuous precipitation days.

Table 1. Characteristics of the rainy season in 2019. For the anomaly of onset/end date, negative/positive means earlier/later than normal;for the anomaly of rainfall amount,negative/positive means less/more than normal.

3. Major meteorological disasters and significant weather and climate events in 2019

In 2019, the losses caused by typhoons, rainstorms and floods, droughts, severe convective weather, lowtemperature freezing and snow disasters, as well as dust storms, were all relatively limited. Preliminary statistics showed that drought-affected areas accounted for 41% of the total area affected by all meteorological disasters in 2019. Meanwhile, rainstorms and floods,hail, and typhoons, as well as low-temperature freezing and snow disasters, accounted for 35%, 11%, 10%, and 3% of the total area affected by all meteorological disasters in 2019, respectively. Meteorological disasters in 2019 affected 19.26 million ha of crops, caused 828 deaths or missing persons, and direct economic losses of 318 billion yuan. The crop-affected areas, number of deaths or missing persons and direct economic losses were all significantly lower in 2019 compared to their averages over the past 10 years(Figure 3).

3.1 Genesis,intensity,and landfall of typhoons

In 2019,there were 29 typhoons(maximum wind force ≥level 8 near the center)in the Northwest Pacific and the South China Sea, among which five typhoons made landfall. The number of typhoons that were generated was greater than normal, whereas the number that made landfall was less than normal. Compared to the average of the past 10 years,the direct economic losses caused by typhoons were relatively limited in 2019.

Typhoon activities in 2019 exhibited significant seasonal differences,while more typhoons were generated in autumn. Specifically, 16 typhoons were generated in autumn in the Northwest Pacific and the South China Sea,accounting for 55%of the total number of typhoons generated in 2019.In particular,six typhoons were generated in November, which was the most since 1949(tied with November 1991).

Among the five typhoons that made landfall, only Lekima did so as a super typhoon; the others were categorized as tropical storms or strong tropical storms.The average landfall intensity was 27.4 m s?1(level 10),which was weaker than normal (30.7 m s?1, level 11).Lekima was the strongest landfalling typhoon in 2019,ranking the fifth strongest landfalling typhoon on the Chinese mainland and third strongest landfalling typhoon in Zhejiang Province since 1949, respectively.Following its landfall on 10 August,it stayed on land for as long as 44 hours and led to extensive damage across nine provinces (cities), affecting 14.024 million people,causing 70 deaths or missing persons, and resulting in direct economic losses of 51.53 billion yuan.

Figure 3.China’s major weather and climate events during 2019.

3.2 Rainstorm events and their associated damage

In 2019, 43 rainstorm events occurred across China,which was more than normal. However, the impacts of floods were generally localized, and the losses were relatively limited.

In summer, there were 18 rainstorm processes, causing rising river water levels,flooded farmland,and urban waterlogging in some areas.During 6-13 June,in central and southern Hunan,Jiangxi,southern Zhejiang,Fujian,Guizhou, northern Guangxi, and central and eastern Guangdong, the cumulative rainfall was 100-350 mm,with the maximum rainfall locally totaling 832 mm in Guilin,Guangxi.During 3-10 July,heavy rainfall occurred again in most areas south of the Yangtze River. The cumulative rainfall was 250-400 mm in southwestern Zhejiang,northern Fujian,central Jiangxi,and southeastern Hunan, with four stations in Jiangxi and Hunan recording their highest amounts of continuous precipitation since records began.

During 1-23 July,three heavy rain processes occurred in Pingdi village of Shuicheng County,Guizhou Province,with cumulative rainfall of 288.9 mm. On 23 July,a massive landslide disaster was caused by continuous heavy rain, causing 52 deaths or missing persons and direct economic losses of 190 million yuan.

From 19-22 August,the western Sichuan basin experienced heavy rain, with a maximum rainfall total of 316.3 mm in Lushan County.There were 20 stations with daily precipitation that exceeded 50 mm, with a peak amount of 155.9 mm in Dujiangyan. Heavy rain led to landslides and debris flows in Wenchuan, amongst other locations.

In 2019, the autumn rain in West China started earlier and ended later,with more rainy days and abundant precipitation.In southern Shaanxi,central Sichuan,and northwestern Chongqing, rainy days were 8-12 d more than normal. Affected by heavy rainfall, some farmland was flooded, towns and cities experienced severe waterlogging, and there were even landslides and debris flows in some local areas,causing casualties and losses of property.

3.3 High-temperature days and their regional features

In summer 2019, the number of high-temperature days(daily maximum temperature ≥35°C)in China was 10.0 d,which was 3.1 d more than normal. High-temperature days were more frequent than normal across most of China in summer,being 10 d more than normal in southeastern Hebei, central and western Shandong, northeastern Henan, most of Hubei, Hunan, most of Jiangxi,central and western Fujian, northwestern Guangdong,northeastern Guangxi,and Hainan.

From mid-April to late June, Yunnan experienced extreme high temperature. The mean temperature as well as the number of high-temperature days in Yunnan were both the highest they had been since 1961. A total of 24 stations, such as Yuanjiang (43.1°C),Jinghong (41.3°C), and Funing (40.3°C) in Yunnan recorded their highest daily maximum temperature.

From late May to late July,Shandong experienced high temperatures.The mean temperature and the mean maximum temperature, as well as the number of hightemperature days in Shandong, were all the highest they had been since 1961. A total of 15 stations reached the extreme high temperature event standard, with the daily maximum temperature at Linqu,for instance,being 40.3°C.

From late July to early October,a large-scale heatwave occurred in Jiangnan and South China. The number of high-temperature days in Jiangnan, South China, and eastern Southwest China was 21.1 d,which was the highest since 1961. In particular, the heatwave covered its widest range and had its strongest intensity in August.In Hubei, Sichuan, Chongqing, Hunan, Jiangxi, Zhejiang,Fujian,Guangdong,and Guangxi,the average number of high-temperature days was 14.2 d,which was 7.7 d more than normal and ranked the highest it had been since 1961.A total of seven stations,such as Fengjie(42.4°C,in Chongqing)and Yicheng(40.0°C,in Hubei),recorded their highest daily maximum temperature since records began.The continuous heatwave had a considerable impact on power supply,human health,etc.

3.4 Obvious regional and periodic droughts

Droughts in China in 2019 were relatively limited, but regional and periodic droughts were obvious.

From March to May,periodic spring droughts occurred in North China, Huanghuai, and Jianghuai. From April to June, Yunnan experienced severe spring-summer droughts. From late July to mid-November, the middle and lower reaches of the Yangtze River experienced serious summer-autumn droughts. The average precipitation in Hubei, Hunan, Jiangxi, Jiangsu, Anhui, Zhejiang, and Fujian was the lowest it had been since 1961,whereas the temperature was the highest. From September to early October, meteorological droughts developed rapidly. On 4 October,moderate to extreme meteorological droughts covered an area of 901 000 km2. Droughts affected the growth of crops in the above areas and led to a high risk offire inforests and grasslands,whichalso caused the water level of rivers and lakes to decrease significantly.

3.5 Convective weather events and their associated economic losses

In 2019, localized strong convective weather events,such as strong winds, hail, tornadoes, and lightning,were less common than on average over the past five years. The economic losses due to strong convective weather were generally light as well. However, on 3 July a rare strong tornado hit Kaiyuan, Liaoning Province, with an intensity of level 4 (equivalent to level EF4 in USA, with a maximum wind speed of more than 74 m s?1). Some houses along the pathway of the tornado collapsed,trees and telephone poles were broken,and cars were thrown into the air,affecting a total of 28 000 people in Kaiyuan,causing six deaths,impacting 9733 ha of crops,and resulting in direct economic losses of 1.08 billion yuan.

3.6 Low-temperature freezing and snow disasters

In 2019, low-temperature freezing and snow disasters affected a total of 585 700 ha of crops, with direct economic losses of 2.77 billion yuan.Compared to the average of the past 10 years, the economic losses in 2019 were obviously light.

In early 2019, snowstorms occurred frequently in Qinghai.In particular,Yushu experienced 12 severe snowfall events in succession,with the snowfall amount as well as the number of snowfall days both reaching their highest on record for the same period.The maximum snow depth in Maduo and Zaduo reached 22 cm and 19 cm, respectively. According to statistics, 207 000 people in Guoluo,Yushu,and Haixi were affected and 53 000 livestock were killed,causing direct economic losses of 210 million yuan.

From January to February, rare low-temperature and rainy weather occurred in southern China.The temperature in central and western Jiangnan,Jianghan,northern South China, and eastern Guizhou was lower than normal, while the precipitation in eastern Jiangnan and western South China was generally 50%-100% more than normal. The numbers of rainy days in southern Jianghuai, Jiangnan, northern South China, and southeastern Guizhou were 8-12 d more than normal,and the anomalies of sunshine hours were less than 50%. The continuous rainy weather had certain negative impacts on agriculture,spring tea,transportation,power supply,and human health in parts of southern China.

3.7 Dust storms in spring and their influence

In spring, there were 10 dust weather events in northern China, which was seven fewer than normal, and among which three were sandstorms or strong sandstorms.Meanwhile,there were 3.2 dust weather days in northern China, which was 1.8 d less than normal. The sandstorm weather event during 19-21 March was the strongest in 2019. Wensu and Xinhe in Xinjiang experienced dust storms, and strong dust storms hit parts of the southern Xinjiang basin.Due to this event,35 flights were cancelled and more than 5200 passengers were affected in Hetian on 20-21 March.

4. Conclusion

The climate in China in 2019 was warmer (0.79°C above normal) and wetter (2.5% above normal) than normal.Multiple high-impact weather and climate events occurred in2019,suchastyphoons,rainstorms,heatwaves,droughts,convective weather events,low-temperature freezing and snow disasters,dust storms,etc.Overall,in 2019,the area of affected crops,the numbers of deaths and missing persons,and the quantity of direct economic losses were all significantly lower than average over the past 10 years.

Acknowledgments

The main results of this report are based on the latest climate monitoring status given by the operational system of the National Climate Center. We appreciate our colleagues’ hard work on climate monitoring and system developments. We would also like to thank Prof. Xukai ZOU, Prof. Zunya WANG, Prof. Yanju LIU, Prof. Ge GAO, Prof. Bing ZHOU, Dr. Yundi JIANG, Ms Lin ZHAO,Mr.Shuai SHI,and Mr.Tong CUI for their contributions.

Disclosure statement

No potential conflict of interest was reported by the authors.

Funding

This work was jointly supported by the National Key R&D Program of China [grant number 2018YFE0196000] and the National Science and Technology Fundamental Resources Investigation Project[grant number 2017FY101201].