The fall armyworm(FAW),Spodoptera frugiperda,is a migratory noctuid pest that has recently invaded eastern Asia.From 2017 up till 2020,searchlight trapping was used to assess the extent of FAW migration across the Sou...The fall armyworm(FAW),Spodoptera frugiperda,is a migratory noctuid pest that has recently invaded eastern Asia.From 2017 up till 2020,searchlight trapping was used to assess the extent of FAW migration across the South China Sea.Molecular and morphology-based identification confirmed that FAW made its first appearance on Yongxing Island on 11 April 2019,with most trapped individuals belonging to the S.frugiperda"corn-strain".Carbon isotope analysis further showed that FAW moths originated from C4 host plants,while trajectory analyses revealed that migratory S.frugiperda adults are able to cross the South China Sea and enter China's Mainland.This long-distance migration process plausibly results in frequent genetic mixing between domestic FAW populations and those of neighboring Southeast Asian countries.Overall,this work provides unique insights into FAW migration across eastern Asia and ultimately can help advance pest forecasting,risk assessment and area-wide pest management.展开更多
The method of cross-ocean GPS long distance rapid static positioning has become one of the main technical means of GPS static positioning away from the mainland. The key technology had been analyzed in-cluding data pr...The method of cross-ocean GPS long distance rapid static positioning has become one of the main technical means of GPS static positioning away from the mainland. The key technology had been analyzed in-cluding data preprocessing and quality control, long distance integer ambiguity resolution and static Kalman filter parameter estimation. Effective data processing method of cross-ocean GPS long baseline rapid static positioning had been proposed. Through the analysis of practical examples of coastal and ocean, the feasibility of cross-ocean GPS long distance rapid static positioning based on the method is testified and verified. The results show that the accuracy of one-hour single baseline static positioning for the 500 - 600 km distance can be better than 10cm in the three-dimensional coordinates ocean environment. , which can suffice static positioning accuracy in the special展开更多
海洋卫星COMs-1((Communication,Ocean&Meteorological Satellite-1)上携带的GOCI(Geostationary Ocean Color Imager)传感器以海洋监测为主,也具备较好的陆地监测潜力,但传感器陆地辐射特性存在偏差。为改善GOCI陆地辐射特性,基于M...海洋卫星COMs-1((Communication,Ocean&Meteorological Satellite-1)上携带的GOCI(Geostationary Ocean Color Imager)传感器以海洋监测为主,也具备较好的陆地监测潜力,但传感器陆地辐射特性存在偏差。为改善GOCI陆地辐射特性,基于MODIS数据,对GOCI可见光和近红外波段开展交叉辐射定标,弥补场地定标成本较高、定标参数更新周期长的不足,拓展其陆地定量遥感监测能力.交叉辐射定标中,考虑了GOCI和MODIS传感器相应波段光谱响应函数之间的匹配;通过辐射传输模拟,订正两传感器观测角度对辐射定标的影响;通过选取两传感器同一过境时刻的数据,降低太阳角度对辐射定标的影响,提高交叉定标精度.通过MODIS数据模拟的GOCI相应波段的表观辐亮度与GOCI实测结果比对,R^2大于0.88。对定标结果进行初步验证,表明交叉辐射定标后,GOCI陆地上的辐射特性满足基本的定量遥感需求。展开更多
基金supported by the National Natural Science Foundation of China(31727901 and 31901873)the Key R&D Projects of Hainan Province,China(ZDYF2018040)+1 种基金the Central Public-Interest Scientific Institution Basal Research Fund,China(CAAS-ZDRW202007)the China Postdoctoral Science Foundation(2019M660896)。
文摘The fall armyworm(FAW),Spodoptera frugiperda,is a migratory noctuid pest that has recently invaded eastern Asia.From 2017 up till 2020,searchlight trapping was used to assess the extent of FAW migration across the South China Sea.Molecular and morphology-based identification confirmed that FAW made its first appearance on Yongxing Island on 11 April 2019,with most trapped individuals belonging to the S.frugiperda"corn-strain".Carbon isotope analysis further showed that FAW moths originated from C4 host plants,while trajectory analyses revealed that migratory S.frugiperda adults are able to cross the South China Sea and enter China's Mainland.This long-distance migration process plausibly results in frequent genetic mixing between domestic FAW populations and those of neighboring Southeast Asian countries.Overall,this work provides unique insights into FAW migration across eastern Asia and ultimately can help advance pest forecasting,risk assessment and area-wide pest management.
文摘The method of cross-ocean GPS long distance rapid static positioning has become one of the main technical means of GPS static positioning away from the mainland. The key technology had been analyzed in-cluding data preprocessing and quality control, long distance integer ambiguity resolution and static Kalman filter parameter estimation. Effective data processing method of cross-ocean GPS long baseline rapid static positioning had been proposed. Through the analysis of practical examples of coastal and ocean, the feasibility of cross-ocean GPS long distance rapid static positioning based on the method is testified and verified. The results show that the accuracy of one-hour single baseline static positioning for the 500 - 600 km distance can be better than 10cm in the three-dimensional coordinates ocean environment. , which can suffice static positioning accuracy in the special
文摘海洋卫星COMs-1((Communication,Ocean&Meteorological Satellite-1)上携带的GOCI(Geostationary Ocean Color Imager)传感器以海洋监测为主,也具备较好的陆地监测潜力,但传感器陆地辐射特性存在偏差。为改善GOCI陆地辐射特性,基于MODIS数据,对GOCI可见光和近红外波段开展交叉辐射定标,弥补场地定标成本较高、定标参数更新周期长的不足,拓展其陆地定量遥感监测能力.交叉辐射定标中,考虑了GOCI和MODIS传感器相应波段光谱响应函数之间的匹配;通过辐射传输模拟,订正两传感器观测角度对辐射定标的影响;通过选取两传感器同一过境时刻的数据,降低太阳角度对辐射定标的影响,提高交叉定标精度.通过MODIS数据模拟的GOCI相应波段的表观辐亮度与GOCI实测结果比对,R^2大于0.88。对定标结果进行初步验证,表明交叉辐射定标后,GOCI陆地上的辐射特性满足基本的定量遥感需求。
