Changes in pick beginning date and frost damage risk of tea tree in Longjing tea-producing area

We analyze the pick beginning date and frost damage risk trends of Jiukeng, Longjing-43, and Wuniuzao tea trees with time, using meteorological data from 12 station pairs over the period 1971–2010 in the Longjing tea-producing area. The pick beginning date of Jiukeng, Longjing-43, and Wuniuzao varieties had no statistically significant trends before 1990. The pick beginning date of Jiukeng variety had statistically significant decreasing trends after 1990, and there were no statistically significant trends in the start date after 1990 for Longjing-43 and Wuniuzao varieties. The average pick beginning dates of Longjing-43 and Wuniuzao varieties before 1990 are later than those after 1990 by 3.8–4.8 and 2.0–3.1 days, respectively. We used the trend of difference between beginning date of tea plucking (BDTP) and 0 °C terminal date to analyze frost damage risk trends. Eleven counties had no statistically significant frost damage risk trends for Jiukeng, Longjing-43, and Wuniuzao varieties, leaving only one county with statistically significant trends.     

EC-thin降水预报与极端天气预报指数在浙江暴雨预报中的检验与释用

利用ECMWF模式降水和极端天气指数资料,以及浙江省68个气象站降水观测资料,评估了ECMWF细网格模式(EC-thin)和降水极端天气指数(EFI)对浙江2018—2020年梅汛期暴雨预报效果。研究表明：对于同一预报时效,随着阈值的增加,EC-thin和降水EFI的暴雨预报评分都呈现“先增加、后减小”的趋势,对于不同预报时效都存在某一阈值使得暴雨预报评分达到最大。从24 h时效到72 h时效,EC-thin的降水预报阈值从45 mm逐渐下降到25 mm,而降水EFI的暴雨预报阈值从07下降到06。EC-thin和降水EFI对暴雨预报的空报率随着阈值的增大而减小,漏报率随着阈值的增大而增大。对于不同预报时效,通过合理组合EC-thin降水阈值和降水EFI阈值,可以得到更好的暴雨预报效果,其评分高于单独使用降水EFI阈值或EC-thin降水阈值得到的评分。     

A Comparative Study of Genetic Variation betwccn Chinese Mitten Crab Eriocheir Sinensis and Hepu Mitten Crab E. Hepuensis

Horizontal starch gel electrophoresis was used to investigate the biochemical genetic structure of Chinese mittencrab Eriocheir sinensis and Hepu mitten crab E. hepuensis. Sixteen putative enzyme-coding loci were examined for forty-nineChinese mitten crabs and thirty-eight Hepu mitten crabs. Nine loci, AAT-1 *, AAT-2 *, G3PDH*, GPI*, IDHP-1 *, IDHP-2 *,MDH-1 *, MDH-2 * and PGM * , are polymorphic in Chinese mitten crab, and seven, AAT-1 *, AAT-2 *, GPI *, IDHP-1 *,MDH-1 *, MDH-2 * and PGM * , are polymorphic in Hepu mitten crab. The proportion of polymorphic loci and the expectedheterozygosity are 0.562 5 and 0.080 3 for Chinese mitten crab, and 0.437 5 and 0.075 4 for Hepu mitten crab. The Nei' s ge-netic distance between two species is 0.002 4.     

A COMBINED REFRACTION-DIFFRACTION-DISSIPATION MODEL OF WAVE PROPAGATION

A numerical model based on the mild-slope equation of water wave propagation over complicated bathymetry,taking into account the combined effects of refraction,diffraction and dissipation due to wavebreaking is presented.Wave breaking is simulated by modifying the wave height probability density func-tion and the wave energy dissipation mechanism is parameterized according to that of the hydraulic jumpformulation.Solutions of the wave height,phase function,and the wave direction at every grid point areobtained by finite difference approximation of the governing equations,using Gauss-Seidel Iterative Method(GSIM)row by row.Its computational convenience allows it to be applied to large coast regions tostudy the wave transformation problem.Several case studies have been made and the results compare verywell with the experiment data and other model solutions.The capability and utility of the model forreal coast areas are illustrated by application to a shallow bay of northeast Australia.     

甘肃桦树沟铁铜矿床地球化学及成因

甘肃桦树为铁铜矿床地质、同位素地球化学、包裹体地球化学、同位素年代学研究表明，该矿床形成于震旦纪裂陷海盆环境，矿床成因属典型的热水沉积成矿。     

Detection of trends in precipitation extremes in Zhejiang, east China

Extreme weather exerts a huge impact on human beings and it is of vital importance to study the regular pattern of meteorological and hydrological factors. In this paper, a selection of seven extreme indices is used to analyze the trend of precipitation extremes of 18 meteorological stations located in Zhejiang Province, east China using the Mann–Kendall test. Then the precipitation trends in the plum season (from May to July) and typhoon season (from August to October) are studied separately. The results show that the precipitation trend varies from east to west. There is a positive trend in the east and a negative one in the west. The largest part of Zhejiang Province shows a positive trend in heavy precipitation and the most significant upward trend is detected in Dinghai with 3.4?mm/year for precipitation on very wet days. Although the upward trend of extreme precipitation is not prevailing, the range of increase in specific areas is apparent, like Dinghai with 1.3?mm/year. Precipitation intensity exhibits an upward trend in most areas and a typical upward trend can be found in Dachendao, Tianmushan, and Yuhuan with 0.04, 0.02, and 0.05?mm/year respectively. Precipitation intensity in both plum and typhoon seasons has increased too, especially for the coastal stations.     

苹果套袋栽培中的气象条件与管理措施

苹果套袋初期,高温易发生果实日灼现象,果实膨大期适温为20-27℃,成熟采收期为13-20℃;花芽分化期土壤保持最大含水量的60%为宜,果实膨大期需水量350 mm左右,成熟期连阴雨天气影响果实着色和采收;日照时数多,光照强,光质好,利于花芽分化、果实糖分积累和着色.摘袋时间因品质不同而异,应在阴天或多云天摘袋;若晴天摘袋,宜在10-14时进行.     

Experimental evidence for eukaryotic fossil preservation: Onion skin cells in silica solution

Research on the origin of eukaryotes often focuses on the exceptional preservation found in silicified Precambrian fossils. Nuclei like subcellular structures in well-preserved fossil becomes confusion and arguments, which focus on whether the partial degradation of prokaryotes produces artifacts that resemble a ‘nucleus’, or fossilized nuclei of eukaryotes. In order to understand the mechanisms of silicification and identify the fossilized subcellular and microstructures in rocks, a series of laboratory controlled experiments were performed for simulating the silicification process. The effects of different silica solutions in eukaryote fossilization were studied in our experiments by exposing onion skin cells (epidermis) to silica solutions. Onion skin provides a good experimental model because of its well characterized cellular structures which are easily observed. The designed experiments revealed that the possibility of onion cell preserved as a “fossil” with nuclear structures, the first week fossilization, or mineralization as rapid as 1 week is important. And the experiment also revealed interactions between silica and the onion skin cell wall surface functional groups were weak. The preservation of nuclei in the onion skin model was due to precipitation in highly supersaturated silica solutions rather than simply the high silica concentration. When the silica gel precipitates slowly at low supersaturation states, the nuclei were not well preserved, but the rapid precipitation at high supersaturated silica conditions preserved nuclear structures. A better understanding of the processes involved in onion skin fossilization will further contribute to issues concerning the silicification of other eukaryotic materials.