Multi-scale remote sensing to support insurance policies in agriculture: from mid-term to instantaneous deductions

ABSTRACT

Climate change is today one of the biggest issues for farmers. The increasing number of natural disasters and change of seasonal trends is making insurance companies more interested in new technologies that can somehow support them in quantifying and mapping risks. Remotely sensed data, with special focus on free ones, can certainly provide the most of information they need, making possible to better calibrate insurance fees in space and time. In this work, a prototype of service based on free remotely sensed data is proposed with the aim of supporting insurance companies’ strategies. The service is thought to calibrate annual insurance rates, longing for their reduction at such level that new customers could be attracted. The study moves from the entire Piemonte region (NW Italy), to specifically focus onto the Cuneo province (Southern Piemonte), which is mainly devoted to agriculture. MODIS MOD13Q1-v6 and Sentinel-2 L2A image time series were jointly used. NDVI maps from MODIS data were useful to describe the midterm phenological trends of main crops at regional level in the period 2000–2018; differently, Sentinel-2 data permitted to map local crop differences at field level in 2016 and 2017 years. With reference to MODIS data, the average phenological behavior of main crop classes in the area, obtained from the CORINE Land Cover map Level 3, was considered using a time series decomposition approach. Trend analyses showed that the most of the crop classes alternated three phases (about 7 years) suggesting that, presently, this is probably the time horizon to be considered to tune mid-term algorithms for risk estimates in the agricultural context. Crop classes trends were consequently split into three phases and each of them modeled by a first-order polynomial function used to update correspondent insurance risk rate. Sentinel-2 data were used to map phenological anomalies at field level for the 2016 and 2017 growing seasons; shifts from class average behavior were considered to locally and temporarily tune insurance premium around its average trend as described at the previous step. Synthesizing, one can say that this approach, integrating MODIS and Sentnel-2 data, makes possible to locally and temporarily calibrate premiums of indexed insurance policies by describing the average trends of crop performance (NDVI) at regional level by MODIS data and refining it at field and specific crop level by Sentinel-2 data.     

江淮梅雨与东亚副热带夏季风进程变异的关系

根据中国气象局《梅雨监测业务规定》中的入、出梅标准,结合1960—2016年全国661个常规气象站逐日气象资料,以及NCEP/NCAR月平均再分析资料,分析了江淮梅雨和东亚副热带夏季风进程变异的时空特征,提取季风关键区(32°~34°N,112°~120°E,包含17个站点),并分析了江淮梅雨和季风关键区的联系与成因。结果表明:1960—2016年平均梅雨期为6月8日—7月15日,平均梅雨量为303 mm。比东亚平均梅雨季的开始时间早9 d,比其结束时间晚7 d。梅雨量在近57 a中也呈波动式变化,但整体为上升趋势。入梅越早,出梅越晚,则梅雨期越长,梅雨量越多。副热带夏季风推进到关键区的平均时间为5月19日,其在1970s末和1990s末分别发生了由偏晚向偏早和由偏早向偏晚的突变。夏季风到达关键区偏早时,出梅日偏晚,梅雨量偏多,季风到达偏晚时,出梅日偏早,梅雨量偏少。副热带夏季风推进时间和江淮梅雨量呈全区一致的负相关,负相关区位于湖南、湖北及江西三省临近的两湖地区。东亚副热带夏季风到达关键区时间偏早(晚)年,500 hPa高度场上乌拉尔山—鄂霍茨克海为正(负)距平,阻塞高压增强(减弱);日本海附近为负(正)距平,东亚大槽加深(西退北缩),加强(削弱)了槽后冷空气向南输送且不(有)利于中低纬度副热带高压的北跳,西太平洋副热带高压中心强度增强(减弱),位置偏西(东),其西北侧的西南暖湿气流输送加强(减弱),江淮地区有水汽的辐合(辐散),有(不)利于梅雨量偏多。     

GPM卫星降水数据在沿海地区的适用性分析——以三亚市为例

选取2016年1—12月GPM(Global Precipitation Measurement)卫星的IMERG月尺度降水数据为研究对象,以同时期的气象站点实测降水数据为参考,利用相关系数、标准偏差、相对误差等多种统计分析指标对其在沿海地区估测能力进行评价。结果表明:IMERG月尺度降水量与站点实测降水数据相关性较好,IMERG估测的降水与气象站点实测降水量的时空变化规律也较为一致,但是量化到具体数值而言,其对山区、海岛站的估测能力不及地势平坦的区域;同时,选取降水个例对IMERG日尺度和半小时尺度降水数据的分析表明,日尺度IMERG估测的不同等级降水量也存在偏差,半小时尺度IMERG降水数据对海岛站的降水估测偏高。总体而言,IMERG降水数据对降水的时间变化规律和空间分布格局估测较为合理,但是对山区、海岛地区,其降水估测值还存在偏差,在今后应用中需结合地形特征加以合理利用。     

中国近代金矿开发概貌

总结了我国清末至民国初期(1840—1920年)长达80年的金矿开发概貌,按现行政区划,共涉及21个省。对各省的金矿,既扼要探讨历史沿革,又尽量地汇集具体产金地名及有关地质矿产信息,期望达到治史与古为今用相结合的双重目的。     

一降水工程的施工和从中引出的思考

基坑降水是岩土工程中经常遇到的施工问题。本文展示了一个降水工程实例，从中引伸出本工程尚未遇到而在其他项目中可能会出现并应及时解决的一些技术问题，引起同行的关注与重视。     

Statistical Downscaling Based on Dynamically DownscaledPredictors： Application to Monthly Precipitation in Sweden

A prerequisite of a successful statistical downscaling is that large-scale predictors simulated by the General Circulation Model (GCM) must be realistic. It is assumed here that features smaller than the GCM resolution are important in determining the realism of the large-scale predictors. It is tested whether a three-step method can improve conventional one-step statistical downscaling. The method uses predictors that are upscaled from a dynamical downscaling instead of predictors taken directly from a GCM simulation. The method is applied to downscaling of monthly precipitation in Sweden. The statistical model used is a multiple regression model that uses indices of large-scale atmospheric circulation and 850-hPa specific humidity as predictors. Data from two GCMs (HadCM2 and ECHAM4) and two RCM experiments of the Rossby Centre model (RCA1) driven by the GCMs are used. It is found that upscaled RCA1 predictors capture the seasonal cycle better than those from the GCMs, and hence increase the reliability of the downscaled precipitation. However, there are only slight improvements in the simulation of the seasonal cycle of downscaled precipitation. Due to the cost of the method and the limited improvements in the downscaling results, the three-step method is not justified to replace the one-step method for downscaling of Swedish precipitation.     

高原季风强弱对南亚高压活动的影响

分析了高原季风强弱对夏季南亚高压活动和三峡库区旱涝的影响,揭示了如高原夏季风偏强(弱),育藏高原上空及其以东地区100hPa南亚高压也偏强(弱),位置偏北偏东(偏南偏西)。高原季风强年,南亚高压脊线6月北跳比多年平均早1候,8月南撤晚1～2侯;高原季风弱年。脊线北跳晚1～2候,南撤早1候。同时显示了高原夏季风强年,5～6月三峡库区降水随着南亚高压脊线北移而增多,7～8月三峡库区降水减少;高原夏季风弱年,主汛期前期库区降水少,后期降水略有增多。     

A case study of the improvement of soil moisture initialization in IAP-PSSCA

A prediction system is employed to investigate the potential use of a soil moisture initialization scheme in seasonal precipitation prediction through a case study of severe floods in 1998. The results show that driving the model with reasonable initial soil moisture distribution is helpful for precipitation prediction,and the initialization scheme is easy to use in operational prediction.     

Gamma Emitters on Micro-Becquerel Activity Level in Air at Kraków (Poland)

The Petryanov air filters combined into half-year sets were analyzed for the presence of ⁴⁰K, ¹³⁷Cs and ²²Na by means of low-background gamma rays spectrometry. Each sample contains aerosols from more than 1 Mm³ of air. Samples were collected in ground level air at Kraków (Southern Poland) from 1996 to 2002. Activity concentrations of ⁴⁰K are almost constant with the mean of 14.7± 4.5 Bq m^–3. Activity concentrations of ¹³⁷Cs, which are on the level of single Bq m^{– 3} show exponential decrease with effective half-life time of 7.07± 0.77 years. The cosmogenic ²²Na shows a strong seasonal variation with significant different mean values activity concentration between 0.333± 0.095 Bq m^–3 and 0.137± 0.045 Bq m^–3, for summer and winter, respectively. Moreover, the activity ratio for two cosmogenic radionuclides: ²²Na and measured previously ⁷Be show also changes with statistically significant seasonal differences. The lower values were found during winters. The mechanisms which might govern this ratio are discussed. The conclusion is that transport of ²²Na during summer seems to be so much effective, that results in kind of relative depletion of stratosphere of this nuclide.     

秋季冷云结构及人工增雨可播性区的评估

利用装备有机载云粒子测量系统、温湿仪和GPS的增雨飞机,在秋季的一次作业中获取的资料与同期的天气和卫星资料,对这次作业的冷云结构进行分析,对作业的可播性做了评估,分析结果表明,75％的时段在强可播区作业,25％在不可播区。云中自然降水效率低,具有较好的增雨催化潜力。