High-resolution precipitation data is conducive to objectively describe the spatial-temporal variability of regional precipitation,and the study of downscaling techniques and spatial scale effects can provide technica...High-resolution precipitation data is conducive to objectively describe the spatial-temporal variability of regional precipitation,and the study of downscaling techniques and spatial scale effects can provide technical and theoretical support to improve the spatial resolution and accuracy of satellite precipitation data.In this study,we used a machine learning algorithm combined with a regression algorithm RF-PLS(Random Forest-Partial Least Squares)to construct a downscaling model to obtain three types of high-resolution TRMM(Tropical Rainfall Measuring Mission)downscaled precipitation data for the years 2000-2017 at 250 m,500 m,and 1km.The scale effects with topographic and geomorphological features in the study area were analysed.Finally,we described the spatial and temporal variation of precipitation based on the optimal TRMM downscaled precipitation data.The results showed that:1)The linear relationships between the TRMM downscaled precipitation data obtained by each of the three downscaled models(PLS,RF,and RF-PLS)and the precipitation at the observation stations were improved compared to the linear relationships between the original TRMM data and the precipitation at the observation stations.The accuracy of the RF-PLS model was better than the other two models.2)Based on the RF-PLS model,the resolution of the TRMM data was increased to three different scales(250 m,500 m,and 1 km),considering the scale effects with topographic and geomorphological features.The precipitation simulation effect with a spatial resolution of 500 m was better than the other two scales.3)The annual precipitation was the highest in the areas with extremely high mountains,followed by the mediumhigh mountain,high mountain,medium mountain,medium-low mountain,plain,low mountain,and basin.展开更多
Background Different diagnostic and grading systems of conjunctivochalasis have resulted in apparent disparity between the prevalence rates of recent population-based studies.This study aimed to investigate the dispar...Background Different diagnostic and grading systems of conjunctivochalasis have resulted in apparent disparity between the prevalence rates of recent population-based studies.This study aimed to investigate the disparity between 4-level system cited from Meller and Tseng in 1998 （abbreviated here as Meller＇s system） and 5-level system modified from Meller＇s system cited from Zhang and associates （abbreviated here as Zhang＇s system） regarding the diagnosis and the patients＇ preferences for the treatment of conjunctivochalasis in the general population.Methods A total of 546 senile residents living in the Guiyangyuan community of Shanghai,China,participated in the study.The diagnostic criteria for conjunctivochalasis were based on two diagnostic grading systems：Meller＇s system and Zhang＇s system,which was modified from Meller＇s system.The participants＇ preference regarding medical treatment for conjunctivochalasis was determined according to the response to a question.One year later,a follow-up interview determines whether the patient had undergone surgery for conjunctivochalasis.Results With Meller＇s system,398 participants were confirmed as having conjunctivochalasis,and the prevalence rate was 72.89％.According to Zhang＇s system,only 213 participants were diagnosed as having conjunctivochalasis,and the prevalence rate was 39.01％.A total of 109 eyes underwent medical treatment or surgery for conjunctivochalasis in the following year,including eight eyes that were diagnosed as grade Ⅱ and 101 eyes that were diagnosed as grade Ⅲ according to Meller＇s system and five eyes that were diagnosed as grade Ⅰ,55 eyes that were diagnosed as grade Ⅱ,31 eyes that were diagnosed as grade Ⅲ,and 18 eyes that were diagnosed as grade Ⅳ according to Zhang＇s system.Conclusion Diagnoses of conjunctivochalasis using Zhang＇s system are more consistent with patient requests and the medical treatment strategies used than diagnoses made using Meller＇s system.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.41941017 and 41877522)the National Key Research and Development Program of China(Grant No.2021YFE0116800)Jiangsu Province Key R&D Program(Social Development)Project of China(Grant No.BE2019776)。
文摘High-resolution precipitation data is conducive to objectively describe the spatial-temporal variability of regional precipitation,and the study of downscaling techniques and spatial scale effects can provide technical and theoretical support to improve the spatial resolution and accuracy of satellite precipitation data.In this study,we used a machine learning algorithm combined with a regression algorithm RF-PLS(Random Forest-Partial Least Squares)to construct a downscaling model to obtain three types of high-resolution TRMM(Tropical Rainfall Measuring Mission)downscaled precipitation data for the years 2000-2017 at 250 m,500 m,and 1km.The scale effects with topographic and geomorphological features in the study area were analysed.Finally,we described the spatial and temporal variation of precipitation based on the optimal TRMM downscaled precipitation data.The results showed that:1)The linear relationships between the TRMM downscaled precipitation data obtained by each of the three downscaled models(PLS,RF,and RF-PLS)and the precipitation at the observation stations were improved compared to the linear relationships between the original TRMM data and the precipitation at the observation stations.The accuracy of the RF-PLS model was better than the other two models.2)Based on the RF-PLS model,the resolution of the TRMM data was increased to three different scales(250 m,500 m,and 1 km),considering the scale effects with topographic and geomorphological features.The precipitation simulation effect with a spatial resolution of 500 m was better than the other two scales.3)The annual precipitation was the highest in the areas with extremely high mountains,followed by the mediumhigh mountain,high mountain,medium mountain,medium-low mountain,plain,low mountain,and basin.
文摘Background Different diagnostic and grading systems of conjunctivochalasis have resulted in apparent disparity between the prevalence rates of recent population-based studies.This study aimed to investigate the disparity between 4-level system cited from Meller and Tseng in 1998 （abbreviated here as Meller＇s system） and 5-level system modified from Meller＇s system cited from Zhang and associates （abbreviated here as Zhang＇s system） regarding the diagnosis and the patients＇ preferences for the treatment of conjunctivochalasis in the general population.Methods A total of 546 senile residents living in the Guiyangyuan community of Shanghai,China,participated in the study.The diagnostic criteria for conjunctivochalasis were based on two diagnostic grading systems：Meller＇s system and Zhang＇s system,which was modified from Meller＇s system.The participants＇ preference regarding medical treatment for conjunctivochalasis was determined according to the response to a question.One year later,a follow-up interview determines whether the patient had undergone surgery for conjunctivochalasis.Results With Meller＇s system,398 participants were confirmed as having conjunctivochalasis,and the prevalence rate was 72.89％.According to Zhang＇s system,only 213 participants were diagnosed as having conjunctivochalasis,and the prevalence rate was 39.01％.A total of 109 eyes underwent medical treatment or surgery for conjunctivochalasis in the following year,including eight eyes that were diagnosed as grade Ⅱ and 101 eyes that were diagnosed as grade Ⅲ according to Meller＇s system and five eyes that were diagnosed as grade Ⅰ,55 eyes that were diagnosed as grade Ⅱ,31 eyes that were diagnosed as grade Ⅲ,and 18 eyes that were diagnosed as grade Ⅳ according to Zhang＇s system.Conclusion Diagnoses of conjunctivochalasis using Zhang＇s system are more consistent with patient requests and the medical treatment strategies used than diagnoses made using Meller＇s system.
