Based on long-term remote sensing products, this paper constructs evaluation indicators for surface high temperatures and analyzes the distribution characteristics of surface high temperatures in Hunan Province over the past 20 years, aiming to provide technical references for agricultural production, disaster prevention and mitigation. Firstly, the daily surface high temperature dataset are calculated using long-term data regression of MYD11A1, MYD13A1 and MYD09GA from 2002 to 2021. The percentage method, percentile method and trend ratio method are used to construct remote sensing evaluation indicators for surface high temperatures, then the spatial and temporal distribution characteristics of surface high temperatures are analyzed. The results indicate that when using the proportion of areas with daily surface temperatures greater than or equal to 45 ℃ as the threshold for classifying surface high temperature levels on a daily scale, it aligns best with meteorological warning indicators. The annual maximum surface high temperature in Hunan Province showed a significant increase with 2013 as a turning point. The extreme threshold for annual surface high temperatures in Hunan Province (ranging from 40.2 to 64.1 ℃), determined using the percentile method, can serve as an evaluation metric for high temperature intensity. Additionally, using the trend rate of surface high temperatures in Hunan Province to evaluate the increase or decrease trends of annual surface high temperatures has good application value. Rapid warming in the Changsha-Zhuzhou-Xiangtan urban agglomeration and the Dongting Lake area, as well as extreme high temperatures in the Hengshao drought corridor, require special attention in the future.

The 36 458 cases of coronary heart disease (CHD) and cerebral infarction (CI) in Beijing from 2008 to 2012 were collected. Based on the fundamental impact of solarterrestrial relationship on temperature change between neighboring days (TCN), a year was divided into two periods dominated by opposite TCN period in this study. The results show that high morbidity of CHD generally occurred in periods from awakening of insects to grain rain, as well as from white dew to winter solstice, which accompanied by large TCN period. In contrast, low morbidities of both CHD and CI took place in the period from grain in ear to summer solstice, which accompanied by small TCN period. Stronger effects of positive TCN period were revealed on young and middleaged (less than and equal to 65 years old) CHD patients than that on the old group (more than 65 years old) by timeseries models, whose relative risk (RR) was up to 1.31. The elderly suffering from CHD were sensitive to negative TCN period, regardless of background temperature trends. Furthermore, in negative TCN period, positive TCN could elevate the highest CI risk for young individuals (less than 45 years old) immediately (RR was equal to 1.23). In conclusion, the shortterm effects of TCN on cardiovascular and cerebrovascular diseases were significant, and seasonal temperature trends modified TCNcardiovascular morbidity associations significantly.