The Xinjiang Institute of Habitats has made progress in the study of global flood occurrence time and driving mechanism

Floods are among the most frequent and costliest natural disasters in the
world.
The intensification of the water cycle in the context of warming will change the size, frequency and timing
of global floods.
Most studies have focused on trends in flood intensity and frequency, while relatively few studies have been conducted on changes in the timing of flood occurrence, mainly at regional or national
scales.

In response to the above problems, Chen Yaning's team from the State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, selected 6167 hydrological stations based on GRDC dataset and GSIM dataset, and evaluated the change trend
of global flood occurrence time.
By analyzing the three main factors affecting flood occurrence, namely 7-day maximum precipitation, 7-day maximum soil water surplus and 7-day maximum snowmelt, the leading factors
of flood occurrence time change in different regions were analyzed.

The results show that there are significant regional differences in the dates of flooding globally: for the western coast of the Americas, Western Europe and the Mediterranean, flooding occurs mainly in winter (December to February), for North America, the Alps, the Indian Peninsula, Central Asia, Japan and other regions, flooding occurs mainly in summer (June to August), and in South Africa and northern Australia, flooding occurs mainly in the southern hemisphere summer (December to February).

The trend of flood occurrence time ranges from -22 days/10a (flood occurrence earlier) to 28 days/10a (flood occurrence delay).

In North America, Europe and northeastern Australia, flooding trends are generally in advance, while in the Amazon, the Cerrado, South Africa, India and Japan, there are delayed occurrences
.
Earlier flood timing in North America and Europe was caused by earlier snowmelt, while delayed extreme soil moisture surpluses and precipitation combined to delay flooding in monsoon regions
.
The results are of great significance for understanding the temporal changes of floods on a global scale, and provide a scientific basis
for coping with and adapting to flood risks caused by global change.

The relevant results were published in Scientific Reports under the title "Shifting in the Global Flood Timing", and the first author of the paper is Fang Gonghuan, an associate researcher
at Xinjiang Shengdi Institute.
The research was supported
by the National Natural Science Foundation of China and the Youth Promotion Association of the Chinese Academy of Sciences.
Article link:

Figure 1.
Trends in the timing of global floods from 1970 to 2010 (a).

Box plots b-f show the relationship between the trend of flood occurrence time and the mean flood occurrence date (b) in the northern hemisphere, the average flood occurrence date (c), latitude (d), hydrological station elevation (e), and catchment area (f
).
Subplot (g) shows multiple linear regression
between flood temporal trends and flood occurrence date, latitude, elevation, and area.