Assessing vegetation dynamics in the Three-North Shelter Forest region of China using AVHRR NDVI data

The Three-North Shelter Forest Programme (TNSFP) covers 551 Chinese counties and an area of 4,069,000 km² mostly in arid and semi-arid regions. In this paper, we discuss the temporal and spatial changes in value of the normalized-difference vegetation index (NDVI) in this region, and the relationships between NDVI and climatic factors (temperature and precipitation) based on NOAA Advanced Very High Resolution Radiometer Global Inventory Modeling and Mapping Studies NDVI data with 8-km resolution from 1982 to 2006. During the past 25 years, the vegetation cover has generally increased in eastern regions of China and the oasis in the north piedmont of Tianshan Mountains, but has decreased northwest of Xinjiang and in the Hulunbeier Plateau. The multi-year monthly average NDVI distribution map showed that NDVI increased from April to August, but in the western and northern plateau areas, the lower temperatures and high altitude created a shorter growing season (1 or 2 months). The vegetation of the study area has generally increased in the regions covered by the TNSFP. Linear regression analysis of the vegetation cover showed an increasing trend over large areas. The largest annual growth rate per pixel (the slope of the regression) was 0.009; the largest negative annual change was −0.004. The correlation between NDVI and precipitation was higher than that between NDVI and temperature, suggesting that precipitation is the most important factor that affects NDVI changes in the study area, especially for temperate desert vegetation in northwestern China.     

Anomalous atmospheric events leading to Kyushu’s flash floods,July 11–14, 2012

During July 11–14, 2012, deadly floods and landslides triggered by a series of unprecedented heavy rains hit Kyushu, Japan, causing at least 32 deaths and around 400,000 evacuations. We focus on synoptic anomalies identified after inspecting rainfall patterns and documenting the conditions associated with this tragic event using data combined from the Global Rainfall Map in Near Real Time data, the NCEP/NCAR Reanalysis dataset, and the global forecast system. Rainfall maps indicated that there were many heavy rains in Kyushu in these days and this disaster was associated with the pattern of forecasts and standardized anomalies. A weather trough with positive height anomalies appeared, the center of which moved to the north of Japan over this period, which might cause wind anomalies and whereby lots of water vapor were transported to Kyushu area with up to 90 m s^?1, and high values of precipitable water formed with up to 60 mm. These results suggest that a larger-scale pattern is conducive for heavy rainfall and the anomalies put the pattern in context as to the potential for an extreme rainfall event, which can provide insights and methods for predicting extreme events’ or something similar.     

Zircon U–Pb Age and Deformation Characteristics of the Jiama Porphyry Copper Deposit,Tibet: Implications for Relationships between Mineralization,Structure and Alteration

The Jiama copper deposit is one of the largest deposits recently found in Tibet and is composed of three types of mineralization including skarn, hornfels and porphyry. To investigate the relationship between mineralization, structure and alteration, we report new zircon U–Pb age and present field observations on the deformation characteritics associated with the copper mineralization in Jiama. Two main periods of deformation were identified, represented by D₁ and D₂ in Jiama. The first deformation (D₁) occurred around 50 Ma, whereas the second deformation (D₂) that was closely related to mineralization occurred later. Previous zircon U–Pb and molybnite Re–Os dating results indicate that the mineralizatoin occurred at ～15 Ma and thus the D₁ regional deformation significantly occurred before the mineralization time, although the D₁ deformation probably provided important space for the development of significant copper deposition. Our new mapping and observations on the D₂ deformation demonstrate that the mineralization was closely coeval with or slightly later than the time of D₂ deformation. The new U–Pb zircon age further indicates that the aplite formed in ～17.0 Ma and thus the D₂ deformation happened later than this time because the D₂ deformation cut across the aplite, which is proposed to be the key control for copper mineralization. Altered laminated hornfels including three types of alteration (A‐, K‐ and S‐type) were found spatially associated with the D₂ deformation. The type‐A is mainly silicification, with fine sericite or chlorite, as well as abundant disseminated sulphides on fracture surfaces; the type‐S is mainly fine‐grained silicification with patches of chlorite, epidote and common sulphides; the type‐K (potassic alteration) appears to be fine‐grained biotite. Such types of alteration indicate the presence of skarns at depth where ore shoots are located. Taken together, the multiple structural‐magmatic‐mineralization events contributed to the formation of the supergiant Jiama porphyry copper deposit in Tibet. The results have general implication for regional exploration.     

基于STA/LTA和分形维算法的微震事件初至自动拾取方法

精确拾取微地震事件初至是微震定位的关键技术之一。根据STA/LTA和分形维数两种微地震初至拾取方法的原理,采用理论模型数据对两种初至拾取方法进行了测试,并选取不同信噪比的实际数据从初至拾取精度、算法效率两个方面进行了对比。结果表明,对于高信噪比微震事件,两种方法都能获得精度较高的初至,但对于低信噪比微震事件,分形维数与STA/LTA比较其拾取精度相对要高。鉴此,运用STA/LTA和分形维两种算法相结合的微震事件初至拾取方法,对实际数据进行了处理,实现了微震事件初至较为准确的自动拾取。     

村镇建设类型划分的理论与方法研究——以江苏省为例

村镇地区是多要素组合的地域单元,由于区位条件复杂多样,资源禀赋差异明显,村镇建设具有多元发展路径。基于资源环境承载力视角,构建了“压力-状态-响应”框架下的村镇建设分类指标体系,采用单向优势指标和复合指标相对优势判断相结合的划定方法,综合考虑国家和省级功能区划、协调乡镇周边区域功能并衔接省国土空间发展战略,以乡镇为分析单元,建立了省级村镇建设分类综合方案,并以江苏省为案例进行村镇建设类型划分研究。研究结果发现,江苏省仅有29.61%的乡镇为明显的单一建设类型,村镇建设的综合性发展态势明显;村镇建设类型具有明显的地域差异,苏北地区主要以居住类乡镇和生态类乡镇为主,苏中地区种植类乡镇和养殖类乡镇居多,苏南地区则集聚了商旅类和工业类乡镇。以此为基础提出不同村镇建设类型的资源环境承载力提升策略。     

1970—2018年秦岭南北冷季降雪量时空变化及其影响因素

基于72个气象站点逐日观测数据,对1970/1971—2018/2019年秦岭南北冷季（11月~次年5月）降水类型（降雪、降雨和雨夹雪）进行识别;重点关注降雪时空变化特征,探讨降雪与气温、湿球温度的响应关系;依据“夏季-秋季-冬季”Niño 3.4区海温异常状态,细化4种不同发展过程的厄尔尼诺-南方涛动（ENSO）事件,分析降雪异常与不同ENSO事件的对应关系。结果表明：① 相比气候平均态（1970—2000年）,1990—2018年,秦岭南坡（山地暖温带）降雪量下降了3.1 mm,基本与关中平原降雪量（17.1 mm）持平;② 空间趋势上,低海拔河谷地带降雪量以年代波动为主,山地高海拔地区为降雪下降区;③ 秦岭高山地区气温或湿球温度每升高1.0℃,降雪量分别下降23.1 mm和24.3 mm;从地带性角度分析,由北向南气温或湿球温度每升高1.0℃,秦岭南北降雪量分别下降3.0 mm和2.8 mm;④ 当厄尔尼诺/拉尼娜持续型发生时,关中平原降雪异常偏多;当拉尼娜发展型发生时,秦岭山地和大巴山区降雪异常偏少。当厄尔尼诺发展型发生时,秦岭南北降雪异常呈现“东西分异”,秦岭山地东部和关中平原为降雪异常偏少区。     

基于多源遥感和机器学习方法的科尔沁沙地植被覆盖度反演

植被覆盖度是监测生态系统及其功能的关键参数,如何提高大区域植被覆盖度的反演精度,对生态脆弱区环境可持续发展至关重要。本研究基于人工神经网络、支持向量回归和随机森林等机器学习方法,利用无人机、Worldview-2与Landsat 8 OLI遥感数据,对科尔沁沙地植被覆盖度进行多尺度反演。结果表明：随机森林模型比人工神经网络、支持向量回归模型表现佳,可在单元（试验区）、区域（研究区）尺度上较高精度地反演沙地的植被覆盖度,反演值与无人机实测值均在线性水平上呈显著相关（P<0.01）;在单元、区域尺度上,构建的植被覆盖度反演模型测试集R²分别为0.84、0.80,MSE分别为0.0145、0.0370,一致性指数d分别为0.9576、0.8991。利用多源遥感数据和机器学习方法,通过局部区域的高精度反演逐步实现低空间分辨率遥感影像的大区域植被覆盖度反演,不仅可有效提高沙地植被覆盖度的反演精度（R²=0.78,大于0.63）,也为区域生态环境监测与生态系统健康评价提供支持。     

Potential Impact of Tonga Volcano Eruption on Global Mean Surface Air Temperature

The undersea volcano, located in the South Pacific island nation of Tonga, violently erupted from 14 to 15 January 2022. The Tonga volcano eruption has aroused ...     

国内外煤炭资源量报告对比研究——以南澳WINTINNA矿区为例

以南澳州WINTINNA煤炭勘查区为实例,选取以我国《固体矿产资源储量分类GB／T17766—1999）标准为勘查标准的《南澳WINTINNA勘查区详查地质报告》和以《澳大利亚矿产资源和矿石储量公布规范（JORC规范）2004）为标准的《WINTINNA煤炭资源量评述报告》作为对照,从报告结构、矿产资源量估算、煤炭资源量结果、资源量变化原因四个方面进行了详尽的对比研究,通过算理与算法对资源量变化原因进行剖析,深入阐述了以JORC标准为主导的国际资源储量估算领域的指导思想和国际通行估算方法,指出了国内外在煤炭资源储量估算领域的不同,对提高我国的资源储量报告在国外市场上的效力、实现国内外主要资源储量标准分类下该类型资源储量报告的快速准确映射和转换具有实际意义。     

松潘－甘孜南部玛孜措石英闪长岩的地球 化学特征、同位素年龄及其构造意义

玛孜措石英闪长岩体位于松潘 甘孜地体南部的甘孜地体内,地处鲜水河断裂带西南侧。岩体具高钾（3.53%~3.86%）、富钙（4.91%~6.07%）、贫铝（14.60%~15.24%）,铝饱和指数（A/CNK=0.80~0.89）偏低的特征,岩石稀土总量较低,轻稀土中度富集,δEu介于0.46~0.53之间,Eu中度亏损,岩石（87Sr/86Sr）i比值介于0.707407~0.707640,表明岩浆起源于壳 幔混熔或下地壳物质的部分熔融,属下地壳重熔的I型高钾钙碱性花岗岩系列。在微量元素构造环境判别图上,样品都落在岛弧区,反映了石英闪长岩具有与岛弧型花岗岩相似的地球化学性质。岩体具较高的Rb（60.1×10-6~85.9×10-6）、Cs（4.01×10-6~19.62×10-6）含量和K2O/Na2O比值（1.31~1.82）,反映源区可能与黑云母的脱水熔融有关。玛孜措石英闪长岩锆石SHRIMP U Pb年龄为221±2.0 Ma（MSWD=1.4）,显示岩体侵位时代为晚三叠世;而全岩Rb Sr等时线年龄为207.0±2.0 Ma（R=0.9979）,显示岩体就位时代为晚三叠世晚期。玛孜措岩体形成于晚三叠世弧后构造环境,是幔源岩浆的底侵作用导致壳-幔混熔的产物。