Solar Flares with an Exponential Growth of the Emission Measure in the Impulsive Phase Derived from X-ray Observations     

Han Fei-ran  Liu Si-ming 《Chinese Astronomy and Astrophysics》2013

The light curves of solar ?ares in the impulsive phase are complex in general, indicating that multiple physical processes are involved in. With the GOES (Geostationary Operational Environmental Satellite) observations, we ?nd that there are a subset of ?ares, whose impulsive phases are dominated by a period of exponential growth of the emission measure. The ?ares occurred from January 1999 to December 2002 are analyzed, and the results from the observations made with both GOES 8 and GEOS 10 satellites are compared to estimate the instrumental uncertainties. Their mean temperatures during this exponential growth phase have a normal distribution. Most ?ares within the 1σ range of this temperature distribution belong to the GOES class B or C, with the peak ?uxes at the GOES low-energy channel following a log-normal distribution. The growth rate and duration of the exponential growth phase also follow a log- normal distribution, in which the duration is distributed in the range from half a minute to about half an hour. As expected, the growth time is correlated with the decay time of the soft X-ray ?ux. We also ?nd that the growth rate of the emission measure is strongly anti-correlated with the duration of the exponential growth phase, and the mean temperature increases slightly with the increase of the growth rate. The implications of these results on the study of energy release in solar ?ares are discussed in the end.  相似文献   

Comparison of methods for the analysis of New Zealand sea lion,Phocarctos hookeri,milk     

F. G. Riet Saprtza  N. Lopez‐Villalobos  D. D. S. Mackenzie  P. J. Duignan  A. MacGibbon  B. L. Chilvers 《新西兰海洋与淡水研究杂志》2013,47(4):997-1006

Abstract

The milk composition of New Zealand sea lion, Phocarctos hookeri, was determined using standard analytical methods, a MilkoScan? FT 120 and an accelerated solvent extractor (ASE) for fat concentration. The results for fat, protein and total solid concentrations between the different analytical methods were assessed using different measures of statistical fitness including coefficient of determination, concordance correlation coefficient, mean prediction error, and intraclass correlation coefficient. The repeatability and reliability of the results obtained with the calibrated MilkoScan? FT 120 were comparable with those obtained using standard methods, the Roese‐Gottlieb method for fat, Kjeldahl method for protein and gravimetric method for total solids. The MilkoScan? FT 120s are fast and cost‐effective and are widely used in dairy laboratories around the world, which should make them readily accessible to ecologists/biologists studying the milk composition of non‐domestic animals.  相似文献   

Petrographical and geochemical investigation of the Triassic marbles associated with Menderes massif metamorphics,Kavaklıdere,Muğla,SW Turkey     

Metin Bağcı  Yaşar Kibici  Ahmet Yıldız  Ömer Tezcan Akıncı 《Journal of Geochemical Exploration》2010

Vast marble deposits occur in a cover sequence of the Menderes Massif, SW Turkey. Four major marble deposits are recognized in Mu?la province based on the stratigraphic levels. These are Permo-Carboniferous aged black marbles (1), Triassic aged marbles (2), Upper Cretaceous aged marbles (3), and Paleocene aged pelagic marbles (4). This study deals with Triassic aged marbles of the southern part of the Menderes Massif. The Triassic marbles from SW Turkey consist of two big marble horizons in the Çayboyu (ÇM) and Kestanecik (KM) regions. The characteristic samples are collected from different stratigraphic levels in marble deposits in the ÇM and KM horizons. Mineralogical and major, trace, and rare earth element (REE) analyses of marble, limestone, and schist were conducted on these samples to reveal their petrographical and geochemical characteristics. The ÇM horizon is represented by calcitic marble layers. Nickel, cobalt, manganese, and iron elements filled in fractures, fissures, and intergranular spaces of calcite crystals and these elements give the pinky colour to the marble from the ÇM horizon. KM marbles were deformed, metamorphosed, and recrystallized under greenschist facies P–T conditions. As a result of the metasomatic reaction of magnesium and manganese rich fluids with marbles, dolomite, and manganese, minerals such as rhodochrosite and pyrolusite have crystallized along vein walls and layers in the KM horizon. Dolomitization was determined in KM marbles, whereas ÇM marbles show the character of limestone. MgO, MnO, Fe₂O₃, Ni, and Zn contents of marbles from the KM horizon are higher than those of ÇM marbles due to metasomatic reactions. The Sr content in white coloured marbles ranges between 11.20 ppm and 112.20 ppm and this concentration reaches up to 272.70 ppm due to metasomatic reactions and fluid intake. The REE content of Triassic marbles is independent of the abundance of carbonate and the REE enrichment observed due to syn-metamorphic fluid flow. The significant negative Eu anomaly in REE patterns indicates that the protoliths of Triassic marbles are carbonate rocks of sedimentary origin.  相似文献   

基于GIS的叶城县核桃种植气候适宜性精细化区划          下载免费PDF全文

王晓霞  李战超  张山清  刘继疆  王森 《沙漠与绿洲气象(新疆气象)》2022,16(1):138-143

本文以叶城县特色林果—核桃为研究对象，研究叶城核桃种植的气候适宜性，以期充分利用农业气候资源，科学规划叶城县核桃种植布局和发展区域提供气候依据。利用叶城县及其周边20个气象站1981-2019年近39年的气温观测数据和同期核桃生长发育的物候资料，在分析核桃生长发育关键期与光、热、水气候条件关系的基础上，提出影响核桃生长发育的关键气候因子≥10℃积温、冬季最低气温≤-25℃日数、终霜冻日早于≥10℃初日天数作为核桃气候适宜性区划指标，基于GIS空间插值技术对叶城县核桃种植各区划指标因子进行空间特征分析，采用GIS空间加权分析法对核桃种植气候指标进行精细化分区，结果表明：叶城县影响核桃的各指标因子空间分布受海拔高度影响，≥10℃积温总体呈现“北疆多、南疆少、平原和盆地多、 山区少”的格局；最低气温≤-25℃日数呈现由山区向平原逐渐减少的特点；终霜冻日早于≥10℃初日天数的空间分布总体呈现山区少平原多的格局。在上述各指标气候要素空间特征的综合作用下，叶城县核桃种植可分为适宜、次适宜和不适宜三个分区。适宜区主要分布在县域北部海拔低于1400m的平原地带，该区能够满足核桃生长发育和优质高产对热量条件的需求，同时，核桃树遭受越冬冻害的风险很低，春季核桃树展叶、开花和结实期遭受霜冻危害的几率也很低，因此，适宜区是叶城县发展核桃种植业最理想的区域，加之，该区地处叶尔羌河上游流域，土壤肥沃，灌溉有保障，应大力发展优质核桃种植面积。次适宜区分布在县域中部海拔1400～2000m的山前倾斜平原和丘陵地带，该区核桃树具有一定的遭受越冬冻害的风险，不宜大规模发展核桃种植。不适宜区分布在叶城县南部海拔2000m以上的山区，该区域核桃树遭受越冬冻害的风险较高，因此，不宜种植核桃。  相似文献   

1991～1994年El Nio的异常特征的诊断研究          下载免费PDF全文

《气象学报》1998,(5)

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