Since the reform and opening-up in 1978, the urbanization level of our country has been continuously improved and the urban development has made great progress. However, with the rapid expansion of urban construction ...Since the reform and opening-up in 1978, the urbanization level of our country has been continuously improved and the urban development has made great progress. However, with the rapid expansion of urban construction land, the population density and building density have been greatly increased, resulting in the urban heat island effect, which has negative impact on the urban thermal environment and restricts the high-quality development of urbanization. This paper focuses on how the urban surface thermal environment of Hangzhou changes in 20 years. In this paper, the characteristics of land surface temperature (LST) in Hangzhou urban area from 2000 to 2020 were studied by using Landsat images. The radiative transfer equation method is used to retrieve the land surface temperature, and the retrieval results are analyzed. The results show that: 1) the land surface temperature in Hangzhou city area has a slight upward trend in the past 20 years;2) the area of high temperature area is expanding;3) the land surface temperature in the city center area has decreased significantly in the past 20 years, while the ground temperature in other areas around the city center has increased significantly.展开更多
对杭州湾北岸3处现代潮滩沉积物进行高精度粒度分析,查找研究区潮滩不同微相的粒度特征和差异,提取基于粒度分析的潮滩微相识别敏感指标,并将其应用到该区域的全新世钻孔潮滩沉积物中,识别钻孔潮滩沉积微相,据此建立研究区全新世早期的...对杭州湾北岸3处现代潮滩沉积物进行高精度粒度分析,查找研究区潮滩不同微相的粒度特征和差异,提取基于粒度分析的潮滩微相识别敏感指标,并将其应用到该区域的全新世钻孔潮滩沉积物中,识别钻孔潮滩沉积微相,据此建立研究区全新世早期的海平面曲线。研究表明:杭州湾北岸现代高潮滩盐沼沉积物粘土含量明显高于高潮滩下部和中潮滩,而砂含量与之相反;高潮滩盐沼平均粒径等粒度参数明显小于中、高潮滩的粒度参数;盐沼沉积物粒度频率曲线峰态宽缓,明显区别于高潮滩下部和中潮滩。上述现代潮滩微相粒度敏感指标可成功应用到钻孔潮滩沉积微相划分中,并建立了该区域全新世早期海平面曲线。曲线显示,9700~8700 cal a BP期间海平面上升约11.6 m,海平面上升速率可达1.2 cm/a。现代潮滩不同位置沉积物粒度参数的规律性差异可作为潮滩微相识别的有效指标,为古潮滩沉积微相识别和古海平面重建提供参考依据。展开更多
本文采用ECMWF(European Centre for Medium-Range Weather Forecasts)细网格和NCEP(National Centers for Environmental Prediction)模式数据、NCEP 1°×1°再分析资料、降雪加密观测和常规资料,对2022年初的5次降雪过...本文采用ECMWF(European Centre for Medium-Range Weather Forecasts)细网格和NCEP(National Centers for Environmental Prediction)模式数据、NCEP 1°×1°再分析资料、降雪加密观测和常规资料,对2022年初的5次降雪过程进行对比分析,发现5次降雪过程均为雨转雪过程,且持续时间相对较短,平原为雨夹雪或小雪到中雪,山区中到大雪,局部暴雪,数值模式预报的积雪深度与实况相差甚远;大尺度环流形势为500 hPa中低纬南支槽或弱波动配合700 hPa上的暖湿气流和中低层冷空气,造成边界层浅薄的冷垫上温度骤降而在短时间内形成降雪;相较于平原地区,高山区上空温度层结与最大上升运动中心的配置,有利于降雪粒子较长时间维持在有利于枝状雪花的形成区域,且高山区云底云水含量显著偏低、整层温度足够低,故高山区更利于暴雪的形成。展开更多
文摘Since the reform and opening-up in 1978, the urbanization level of our country has been continuously improved and the urban development has made great progress. However, with the rapid expansion of urban construction land, the population density and building density have been greatly increased, resulting in the urban heat island effect, which has negative impact on the urban thermal environment and restricts the high-quality development of urbanization. This paper focuses on how the urban surface thermal environment of Hangzhou changes in 20 years. In this paper, the characteristics of land surface temperature (LST) in Hangzhou urban area from 2000 to 2020 were studied by using Landsat images. The radiative transfer equation method is used to retrieve the land surface temperature, and the retrieval results are analyzed. The results show that: 1) the land surface temperature in Hangzhou city area has a slight upward trend in the past 20 years;2) the area of high temperature area is expanding;3) the land surface temperature in the city center area has decreased significantly in the past 20 years, while the ground temperature in other areas around the city center has increased significantly.
基金国家自然科学基金项目《杭州湾北岸全新世早期(10-9 cal ka BP)高精度海平面重建及沉积环境响应》(批准号:41706098)《基于微体化石识别全新世高海面阶段长江口外水团相互作用及调控机制》(批准号:42076081)。
文摘对杭州湾北岸3处现代潮滩沉积物进行高精度粒度分析,查找研究区潮滩不同微相的粒度特征和差异,提取基于粒度分析的潮滩微相识别敏感指标,并将其应用到该区域的全新世钻孔潮滩沉积物中,识别钻孔潮滩沉积微相,据此建立研究区全新世早期的海平面曲线。研究表明:杭州湾北岸现代高潮滩盐沼沉积物粘土含量明显高于高潮滩下部和中潮滩,而砂含量与之相反;高潮滩盐沼平均粒径等粒度参数明显小于中、高潮滩的粒度参数;盐沼沉积物粒度频率曲线峰态宽缓,明显区别于高潮滩下部和中潮滩。上述现代潮滩微相粒度敏感指标可成功应用到钻孔潮滩沉积微相划分中,并建立了该区域全新世早期海平面曲线。曲线显示,9700~8700 cal a BP期间海平面上升约11.6 m,海平面上升速率可达1.2 cm/a。现代潮滩不同位置沉积物粒度参数的规律性差异可作为潮滩微相识别的有效指标,为古潮滩沉积微相识别和古海平面重建提供参考依据。
文摘本文采用ECMWF(European Centre for Medium-Range Weather Forecasts)细网格和NCEP(National Centers for Environmental Prediction)模式数据、NCEP 1°×1°再分析资料、降雪加密观测和常规资料,对2022年初的5次降雪过程进行对比分析,发现5次降雪过程均为雨转雪过程,且持续时间相对较短,平原为雨夹雪或小雪到中雪,山区中到大雪,局部暴雪,数值模式预报的积雪深度与实况相差甚远;大尺度环流形势为500 hPa中低纬南支槽或弱波动配合700 hPa上的暖湿气流和中低层冷空气,造成边界层浅薄的冷垫上温度骤降而在短时间内形成降雪;相较于平原地区,高山区上空温度层结与最大上升运动中心的配置,有利于降雪粒子较长时间维持在有利于枝状雪花的形成区域,且高山区云底云水含量显著偏低、整层温度足够低,故高山区更利于暴雪的形成。
