青藏高原不同季节地表温度变化特征分析

基于欧洲中尺度气象预报中心(ECMWF)提供的ERA-Interim地表温度,利用经验正交函数(EOF)等方法,分析了青藏高原四季地表温度的时空变化特征.结果发现:青藏高原春、夏、冬季地表温度变化以整体型为主,并且大部地区地表温度呈现升高的趋势;秋季地表温度略有下降趋势,并且以东部和西部地表温度的反向型异常变化最为显著.此外还发现,青藏高原不同季节地表温度的异常变化具有一定的联系,其中整体型变化可以持续3个季节.     

高分辨率卫星影像正射纠正及其在地理国情监测中的应用

摘要：高分辨率影像作为地理国情监测的基础数据源发挥着越来越重要的作用。根据World．View和资源三号卫星影像在地理国情监测地表覆盖项目中的具体应用,对制作地理国情监测作业底图遇到的问题及处理方法进行总结。     

Theoretical and quantitative analyses of the fault slip rate uncertainties from single event and erosion of the accumulated offset

Fault slip rate is one of the most important subjects in active tectonics research, which reveals the activity and seismic potential of a fault. Due to the improvement of dating precision with the development of dating methods, Holocene geological markers, even the young markers of thousands or hundreds of years old, are widely used in fault slip rate calculation. Usually, uncertainties from a single event and erosion of the accumulated offsets are involved in fault slip rate determination. Two types of uncertainties are related to a single event; the first is the time elapsed since the latest (the most recent) event; the second is the period since the formation of the geological marker to the occurrence of the first event. High‐slip‐rate faults are more sensitive to these uncertainties than low‐slip‐rate faults. In this study, we studied quantitatively the effects of a single event on fault slip rate following the three classic earthquake models: the characteristic earthquake, uniform slip and variable slip models. We suggest that the erosion of the accumulated offset–lateral erosion on a strike‐slip fault, should also be considered in fault slip estimation. Therefore, we propose a differential method to obtain a reliable fault slip rate. In the differential method, the slip rate is the ratio of offset differentials and corresponding age differentials between the older and younger terraces along strike‐slip faults. This kind of differential method could avoid the uncertainties from the first and latest events, as well as that from the lateral erosion. By applying the differential method, we got the revised slip rates of ∼5–10 mm/year on the Altyn Tagh and Kunlun faults. These low slip rates could fit previous geodetic and geological fault slip rates and shortening rates as well as the millennial recurrence intervals of strong earthquakes along the major segments of these faults.     

无人船近海水深测量与抗风浪能力评估北大核心CSCD

传统载人测量船吃水深,无法进行浅海水深测量,因此吃水极浅的无人船为近海水深测量提供了新途径。本文利用无人船无验潮测深与GNSS网络RTK技术,在不同的风浪条件下进行了近海水深测量试验;并从轨迹跟踪与水深测量精度方面,定量评估了无人船野外作业的抗风浪能力。结果表明:0~0.3 m浪、0~2级风是无人船近海测量作业的理想风浪阈值;风浪过大会导致无人船路径跟踪精度较低,难以保证测量成果质量。在理想的风浪阈值内,无人船无验潮测深技术能实现近海水深的高精度测量,满足相关测深规范要求,在近海水深与海底地形测量中具有广阔的应用前景。     

高建筑物上闪电普通摄像观测与分析

2009-2010年夏季,在广东省气象局对东南方向的高建筑物上的闪电进行了观测.对获得的普通摄像资料进行了处理和分析,基于对闪电事件引起普通摄像中像素亮度变化的分布特征的分析结果,编写了视频资料处理程序,实现了普通摄像资料中闪电图片的自动提取.在此基础上,统计分析了观测到的广州高建筑物上87次自然闪电的特征,结果表明:这些闪电的持续时间平均为348 ms;对于高度超过500m的建筑物,其上发生闪电的次数明显多于高度低于500 m的建筑物,且闪电的平均持续时间也更长.给出了拍摄到的几幅云下闪电通道呈现蛛状和长距离特征的闪电图片.     

The anomalous variation of the lightning activity in southern China during the 1997/98 El Niño event

This paper presents the EOF analysis results of the lightning density (LD) anomalies for the different seasons in southeastern China and Indochina Peninsula by using the OTD/LIS database (June 1995 to Feb. 2003) of the global LD with 2.5Ü×2.5× resolution offered by Global Hydrology Resource Center. It is shown that the LD positive anomalies in the region occurred at the same time of NINO3 SSTA steep increase in the spring of 1997 and remained to be a higher level till the next spring, as well the corresponding anomaly percent maximum in different seasons was 89%, 30%, 45%, 498% and 55% successively from the beginning to the end of the 1997/98 El Niño event (ENSO). The centre of the LD positive anomalies for the spring or winter season is located at southeastern China and the adjacent coastal areas, but it for the summer or autumn season is located at the southern Indochina Peninsula and Gulf of Thailand, whose position for each season in the ENSO as contrasted with the normal years has a westward shift, and especially for winter or spring season a northward shift at the same time. In addition, an analysis of the interannual variations in the LD anomaly percent, convective precipitation and H-CAPE days in southern China shows that each among the three anomaly percents is correlative with the other for the positive anomaly zone and Kuroshio area. The relative variation of LD during the El Niño period is the highest among the three rates and is larger than that during the non-El Niño period, meaning that the response of lightning activities to the ENSO is the most sensitive in both areas. But the response of lightning activities and precipitation to the ENSO appears to be more complex and diversified either in Kuroshio area or in the Qinghai-Tibet Plateau and northwestern and northeastern China.     

煤层底板突水因素的综合评价：以肥城矿区为例

将系统工程中的层次分析引入煤层底板突水的研究中。以肥城矿区为例，阐述了煤层底板突水因素综合评价方法的应用，使底板突水评价研究从定性向定量转化，对查明底板水文地质条件和突水预测具有重要的指导意义。     

基于网络关注度的安徽省居民省内旅游需求时空特征分析

基于百度指数平台,收集2019年安徽省居民对省内64家典型景区的网络关注度数据,利用季节性强度指数、旅游需求偏好指数和基尼系数分析安徽省居民的旅游需求特征,并对影响因素进行探讨。结果显示:全省居民省内旅游需求呈多岭型,形成4月、7―8月和10月3个需求高峰;单岭型景区各月的旅游需求有较明显差别,双岭型和多岭型的景区无明显旅游需求季节性差别;全省居民旅游需求时间主要受经济发展水平、旅游资源的季节性和独特性、景区开发程度、气候舒适度、节假日的影响;安徽省居民形成3个旅游需求偏好区,分别是皖中皖东南休闲娱乐偏好区、皖南自然观光偏好区和皖西南山岳景观偏好区;全省居民旅游需求空间分布主要受景区密集程度、级别、资源开发程度和空间距离的影响。     

A hybrid model for numerical wave forecasting and its implementation——Ⅱ. The discrete part and implementation of the model

In the first part of the present paper we have explained why we manage to formulate another wave prediction model when so many of them, including the so-called third generation model, have already been in use. The wind-wave part of the proposed model has also been given. Now we proceed to discuss the swell part,the implementation of the model as a prediction method,mumerical experiments done with ideal wind fields and hindcasts made in the Bohai Sea,in the neighboring seas adjacent to China and in the Northwest Pacific.     

Statistical evaluation of the performance of gridded monthly precipitation products from reanalysis data,satellite estimates,and merged analyses over China

Theoretical and Applied Climatology - In this study, we compared the following four different gridded monthly precipitation products: the National Centers for Environmental Prediction version 2...