| 摘要: |
| 【目的】针对目前在气候变化对蒸发皿蒸发量影响研究中所关注的“蒸发悖论”现象，以位于五道沟地区的五道沟实验站气象场1970―2017年实测数据为背景资料。【方法】对蒸发量的年际变化趋势进行分析与预测，对其影响因素（风速、温度、日照时数、水汽压力差、降雨量、相对湿度）应用趋势线分析法进行定性分析，应用熵值法进行综合评价，并深入探讨蒸发皿蒸发量趋势变化的成因。【结果】（1）1970―2017年蒸发量呈明显下降趋势，下降速率为8.7 mm/a，运用灰色系统中的GM(1,1)模型与Verhulst模型对蒸发量的年际趋势进行预测，结果表明GM(1,1)模型预测效果更好。（2）蒸发量与各气象要素的相关关系：风速、日照时数与蒸发量呈正相关关系，气温、相对湿度、降雨量与蒸发量呈负相关关系。1970―2017年间气温每10年平均升高0.25 ℃，水面蒸发每10年平均下降86.9 mm，该区存在“蒸发悖论”现象。（3）线性趋势法与熵值法对各影响因素分析结果一致：风速>气温>相对湿度>日照时数>降雨量>水汽压力差，表明在全球气候变暖的大背景下，风速下降、相对湿度增加和日照时数减少是该区“蒸发悖论”现象的主要因素。（4）日照时数的下降可能是气溶胶含量增多造成的；风速的下降可能与城镇化发展有关，风速减弱可能会引起气溶胶增多；相对湿度的增加，会导致日照时数的减少。【结论】，五道沟地区“蒸发悖论”的成因可能是气溶胶含量的增加，太阳辐射减少，蒸发量下降。该研究为进一步探讨蒸发皿蒸发量变化成因提供依据。 |
| 关键词: 蒸发皿蒸发量；趋势变化；气象因素；五道沟地区 |
| DOI： |
| 分类号:P426.2 |
| 基金项目:国家重点研发计划课题 (No.2017YFC0404504) |
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| "Evaporation Paradox" in Wudaogou Area and Its Causes |
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wangyining
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Nanjing hydraulic research institute,Nanjing
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| Abstract: |
| In view of the current phenomenon of “evaporation paradox” in the study of the impact of climate change on the pan evaporation, background data from the 1970-2017 weather data of the Wudaogou Experimental Station in Wudaogou area. The annual variation trend of evaporation is analyzed and predicted, and the influencing factors (wind speed, temperature, sunshine hours, water vapor pressure difference, rainfall, relative humidity) are qualitatively analyzed by trend line analysis method, and entropy method is applied. Comprehensive evaluation, and in-depth discussion of the causes of changes in the evaporating dish evaporation trend. Research indicates: (1) The evaporation rate showed a significant downward trend from 1970 to 2017, and the rate of decline was 8.7 mm/a. The GM(1,1) model and the Verhulst model in the gray system were used to predict the inter-annual trend of evaporation. The results showed that GM (1,1) The model predicts better results.(2) Correlation between evaporation and various meteorological elements: wind speed, sunshine hours and evaporation are positively correlated, and temperature, relative humidity, rainfall and evaporation are negatively correlated. From 1970 to 2017, the temperature increased by 0.25 °C every 10 years, and the evaporation of water surface decreased by 86.9 mm every 10 years. There is a phenomenon of "evaporation paradox" in this area. (3) The linear trend method and the entropy method are consistent with the analysis results of various influencing factors: wind speed > temperature > relative humidity > sunshine hours > rainfall > water vapor pressure difference, indicating that the wind speed drops in the context of global warming, The increase in relative humidity and the reduction in sunshine hours are the main factors in the “evaporation paradox” phenomenon in the region. (4) The decrease of sunshine hours may be caused by the increase of aerosol content; the decrease of wind speed may be related to the development of urbanization. The decrease of wind speed may cause the increase of aerosol; the increase of relative humidity increases the probability of foggy weather. This will result in a reduction in sunshine hours. In summary, the cause of the “evaporation paradox” inWudaogou area may be an increase in aerosol content. The increase in aerosol content leads to a decrease in solar radiation and a decrease in evaporation. This study provides a basis for further exploration of the cause of changes in evaporating dish evaporation. |
| Key words: Pan evaporation; trend variation; meteorological factors; Wudaogou area |
