Analysis of Intra-annual Heterogeneous Characteristics of Precipitation in Shaoguan City

Based on the daily precipitation data between 1965 and 2009 from 8 rainfall stations in Shaoguan City,the indexes of precipitation concentration degree（ PCD） and precipitation concentration period（ PCP） were calculated. And then inverse distance weighted（ IDW） interpolation method was used to analyze the heterogeneous distribution characteristics of inter-annual precipitation by introducing the spatial distribution of annual mean values,variable coefficients,correlation coefficients with annual precipitation,change trends and composite analysis. The results showed that PCD was mainly decreasing from southeast to northwest in spatial distribution,long-term average annual values of PCP were distributed in the first ten days of June at most region. Annual precipitation increased as PCD increased in southern region,but the change trend was the opposite in northern region. Annual precipitation increased as PCP lagged in most region. PCD and PCP mainly appeared upward trend. Composite analysis of PCD in more-precipitation years was similar to less-precipitation years in spatial distribution,but the PCD in less-precipitation years was higher.Seen from the mean in the whole region,PCP in more-precipitation years lagged about 20 days behind those in less-precipitation years. The research can provide basis for the production of agriculture and industry as well as disaster prevention and reduction.

Combination patterns of precipitation and its concentration degree determining the risk of dengue outbreaks in China

The amount and distribution of precipitation can determine dengue risk by affecting mosquito breeding;however,previous studies failed to incorporate this bivariate characteristic to examine dengue fever transmission.In the present research,nationwide data on daily dengue cases in China between January 2005 and December 2020 were obtained,and the top 12 cities accounting for 78%of total cases were selected for analysis.Precipitation patterns were quantified by weekly precipitation and precipitation concentration degree(PCD).On the basis of the combinations of both parameters,the exposure-response relationships of precipitation with dengue risk were established using generalised additive models,and the high-dengue-risk thresholds of precipitation patterns were further identified.Dengue burden was assessed by calculating attributable dengue cases.For the same amount of precipitation,the dispersed precipitation in the pre-summer rainy season leads to a higher dengue risk in autumn.The weekly precipitation of 100-150 mm and PCD of 0.2-0.4 constitute the highest risk scenario,and the average frequency of precipitation associated with dengue risk in 2013-2020 is 1.6 times higher than that in 2005-2012.A total of 3093 attributable dengue cases are identified.From 2005 to 2020,the amount of dispersed precipitation increased in southern and southwestern China and posed high dengue risks in central China.This study has improved the understanding of the health impacts of irregular rainfall under climate change.Our approach to identifying thresholds provides information for early warning systems and helps reduce the risk of dengue transmission in the long run.

Changes in Temporal Concentration Property of Summer Precipitation in China during 1961–2010 Based on a New Index

Based on the property of entropy,a new index Q was defined to measure the temporal concentration property of summertime daily rainfall in China,based on daily precipitation data collected at 553 observation stations in China during 1961–2010.Furthermore,changes in the temporal concentration property of summer precipitation in China were investigated.The results indicate that the regions with larger Q values were located in most parts of Northwest China and the north of the Yellow River,where daily precipitation tended to become temporally concentrated during the study period.On the contrary,smaller Q values were found in eastern Tibetan Plateau,southeastern Northwest China,and most parts of Southwest and South China.The most obvious increasing trend of Q index was found in South China and most parts of Southwest China,where precipitation showed a temporal concentration trend.However,a decreasing trend of Q index was found in Northwest China,the Tibetan Plateau,and the north of the Huaihe River.Variations of the Q index and the summer rainfall total during 1961–2010 in China both exhibited an increasing trend,implying larger temporal variability in rainfall attributes.It is illustrated that the summer precipitation in general became more temporally concentrated with more intense rainfall events and wetter days.

1960-2011年葡萄牙降水变化（英文）

This study analyses spatial variab （amount and concentration） based on data lity and trends in annual and monthly precipitation from 42 stations in mainland Portugal during the period 1960-2011. Relationships between certain geographic variables （elevation, latitude and longitude） and precipitation variability were also determined in order to check for specific dependencies and spatial patterns in precipitation distribution, concentration and changing trends. Trends and relationships have been analysed using both parametric and non-parametric tests. The results showed that annual precipitation had decreased in all stations and that this trend is statistically significant for most of the time series （70% of the stations showed nega- tive trends with at least a 0.1 significance level）. The Annual Precipitation Concentration In- dex revealed an opposite behaviour pattern, suggesting that even though the annual trend for precipitation amount was negative overall, more than half of the udometric stations registered a more marked seasonality for precipitation during the period 1960-2011. However, only one station showed statistical significant time trend. Regarding the influence of geographical features, latitude is the most important variable, governing spatial distribution and variations in annual precipitation as well as its intra-annual changeability. These important changes in precipitation, involving both amount and concentration, may have severe consequences for ecosystems and societies.