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Special Session 7: Coastal assessments: From implementation to impact: understanding the gap |
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Analysis of variation and regional difference of extreme temperature events in coastal area of China during 1961¡ª2014
Monday 9th @ 1445-1505
Room 5
Xiyong Hou* , Yantai Institute of Coastal Zone Research, CAS
Xiaoli Wang, Yantai Institute of Coastal Zone Research, CAS
Presenter Email: xyhou@yic.ac.cn
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| Based on daily temperature dataset of 156 station records, a set of statistical methods including Trend Analysis, Morlet Analysis, Mann-Kendall test, Accumulative Anomaly, Pettitt test and Principal Component Analysis (PCA) are employed to investigate the spatial and temporal variations of extreme temperature events from 1961 to 2014 in coastal area of China. Results of trend analysis demonstrated that there was an upward trend of warm extremes and a downward trend of cold extremes as well as diurnal temperature range (DTR), the decadal trend rates of night extremes were obviously higher than those of day extremes in coastal area of China. Generally, annual averages decreased for frost days (FD0), ice days (ID0) and diurnal temperature range (DTR) and increased for summer days (SU25), tropical nights (TR20), minimum value of daily maximum temperature (TNx), minimum value of daily minimum temperature (TNn) and growing season length (GSL) from north to south, but varied a little for cool days (TX10p), cool nights (TN10p), warm days (TX90p), warm nights (TN90p), maximum value of daily maximum temperature (TXx), maximum value of daily minimum temperature (TNx), cold spell duration index (CSDI) and warm spell duration index (WSDI) between the sub-regions and the whole coastal area of China. The primary period of extreme temperature indices varied from 2 to 8 year in sub-regions of coastal area of China, and no significant decadal period was detected. The mutation time of extreme temperature indices were mainly during 1980s¡ª1990s in all sub-regions, additionally, mutation time of cold extremes and minimum values of daily maximum (minimum) temperature were earlier than those of warm extremes and maximum values of daily maximum (minimum) temperature. The extreme warm events and extreme value events were tending to be frequent, whereas the extreme cold events decreased gradually. Extreme temperature indices holding high load in the first principal component showed strong positive correlations with each other and exhibited high contributions to daily average temperature and daily maximum (minimum) temperature, however, those extreme temperature indices holding low load in the first principal component presented weak correlations with other extreme indices and showed low contributions to daily temperature for averages and extreme values during the study period. |
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