福建茶叶生产发展途径探讨

福建是我国著名茶区,发展茶叶生产自然条件得天独厚,技术、经济条件良好。茶叶产量位居全国前列,茶质优,闻名中外。生产的茶叶种类多,特种茶多,名茶多,商品性强。茶园分布广泛又相对集中,茶叶单产低。积极发展茶叶生产是发挥优势,振兴福建经济和国家现代化建设之所需。今后发展茶叶生产的途径:(一)努力提高茶叶单产;(二)尽快提高茶叶质量;(三)加速发展特种茶及名茶生产;(四)合理布局茶叶生产。     

成因地质模型法在矿产普查勘探中的作用

本文在阐述成因地质模型法的基本原理及与其它地质理论的联系、矿产资源预测评价方法的发展趋势等问题的基础上,探讨了成因地质模型法在矿产普查勘探中的作用,提出了成因地质模型法不仅是当前矿产资源预测评价的最佳方法,而且可能是矿产资源预测评价方法的发展方向;不仅是研究矿产成因、探讨矿床成因分类的好方法,而且可能是通过“四维空间”全面研究矿床形成机理的普遍适用的综合性地质成矿理论。     

海温场的递归滤波分析

递归滤波(RF)是一种属于经验线性插值类的客观分析方法。因其处理边界域和背景场的独特能力以及在计算机处理上的快速便捷优于其他的传统分析方法,适合于分析诸多资料量大(如卫星资料)、不同来源的不均匀资料。本文主要发展这一客观分析方法在海温场分析上的应用。综合利用各种时空分布和精确度均不相同的海温资料,对几个基本参数的取法进行调试并选取适当的值,分析得出细网格的海温场。结果表明,递归滤波方法不仅灵活简便,而且分析出的海温场质量好,基本上可以反映海温的实际情形。对海温场的分析还可为其他从卫星等提取的非常规资料分析提供借鉴。     

闽南-台湾浅滩渔场鱼类食物网研究

海洋鱼类食物网是海洋生态学基础理论研究之一,从多种海洋鱼类食性类型的综合分析,阐明食物网营养级的能流途径,为改造海洋生态系统,减少食物链的环数而提高水域生产力。因此,深入研究海洋鱼类食物网,对于合理利用海洋渔业资源具有一定的实践意义。近年来,国外在河口红树林群落,以残屑(detritus)为基础的食物网研究已有报道[1];对河口游泳动物食物网也发表过综合论述[2]。     

Forecast Performance of the Pre-operational CMA-TRAMS (EPS) in South China During April - September 2020

The mesoscale ensemble prediction system based on the Tropical Regional Atmosphere Model for the South China Sea (CMA-TRAMS (EPS)) has been pre-operational since April 2020 at South China Regional Meteorological Center (SCRMC), which was developed by the Guangzhou Institute of Tropical and Marine Meteorology (GITMM). To better understand the performance of the CMA-TRAMS (EPS) and provide guidance to forecasters, we assess the performance of this system on both deterministic and probabilistic forecasts from April to September 2020 in this study through objective verification. Compared with the control (deterministic) forecasts, the ensemble mean of the CMATRAMS (EPS) shows advantages in most non-precipitation variables. In addition, the threat score indicates that the CMA-TRAMS (EPS) obviously improves light and heavy rainfall forecasts in terms of the probability-matched mean. Compared with the European Center for Medium-range Weather Forecasts operational ensemble prediction system (ECMWF-EPS), the CMA-TRAMS (EPS) improves the probabilistic forecasts of light rainfall in terms of accuracy, reliability and discrimination, and this system also improves the heavy rainfall forecasts in terms of discrimination. Moreover, two typical heavy rainfall cases in south China during the pre-summer rainy season are investigated to visually demonstrate the deterministic and probabilistic forecasts, and the results of these two cases indicate the differences and advantages (deficiencies) of the two ensemble systems.     

大兴安岭东南坡新生代隆升及地貌演化的裂变径迹研究

通过磷灰石裂变径迹热年代学研究,揭示了新生代时期大兴安岭东南坡平均隆升速率为29.68m/Ma,大约隆升了1 944 m,平均降温103.50℃,平均地温梯度为53.24℃/km。在时间上,其隆升剥蚀具有明显的幕式特点,5次低速和4次高速隆升相间分布。其中,4个高速隆升期分别是距今56.44~49.65Ma、40.40~31.80 Ma2、5.00~17.91 Ma1、1.72~4.45 Ma。在空间上,隆升存在差异,根据其隆升剥蚀情况,可将新生代大兴安岭东南坡的地貌演化分为4个阶段:(1)距今65.50~56.44 Ma为以FT4为分隔点的定点分隔型地貌;(2)56.44~40.40 Ma为挠曲下降型地貌;(3)40.40~8.00 Ma为以FT1为分隔点的定点分隔型地貌;(4)8.00~0.00 Ma为以FT7为分隔点的定点分隔型地貌。在总体隆升的高速期,地貌类型发生转换。     

AN OBSERVATIONAL ANALYSIS OF A TORRENTIAL RAINSTORM IN THE WARM SECTOR OF SOUTH CHINA COASTAL AREAS

On May 20 th 2007, a brief but severe downpour rainstorm occurred in the coastal areas of Maoming and Yangjiang with rainfall of 115 mm per hour. Data from NCEP/NCAR reanalysis with 1°×1° resolution, Doppler weather radar, conventional surface observations, high-altitude radiosonde and wind profiler radar were used to analyze characteristics and contributions of synoptic scale and mesoscale systems during this torrential rainstorm. The results showed that:(1) the storm was caused by a quasi-linear mesoscale convective system(MCS) and the slow-movement of this system was the primary trigger of the torrential downpour;(2) water vapor was abundant, nearly saturated and in steady state throughout the atmosphere before the storm; intrusion of the weak dry and cold air in the middle level and a striking "dry above and wet below " structure had increased the atmospheric instability;(3) low-level southwesterly airflow from a low pressure(trough) at the Beibu Gulf provided abundant water vapor at the onset of the rainstorm; a deep dry layer was formed by dry and cold air behind the high-level trough, which facilitated latent heat release;upper-level divergence and low-level convergence circulations also provided vertical uplift for warm and moist air at the lower level;(4) Topography only played a minor role as the MCS developed and strengthened over relatively flat coastal terrain. Low level density flow induced by convection triggered new convective cell generation at the leading edge of the convective system, thereby playing a key role in the change of temperature gradient at lower layers, and resulting in strengthening atmospheric instability.     

APPLICATION EXPERIMENT OF ASSIMILATING RADAR-RETRIEVED WATER VAPOR IN SHORT-RANGE FORECAST OF RAINFALL IN THE ANNUALLY FIRST RAINY SEASON OVER SOUTH CHINA

A scheme of assimilating radar-retrieved water vapor is adopted to improve the quality of NWP initial field for improvement of the accuracy of short-range precipitation prediction. To reveal the impact of the assimilation of radar-retrieved water vapor on short-term precipitation forecast, three parallel experiments, cold start, hot start and hot start plus the assimilation of radar-retrieved water vapor, are designed to simulate the 31 days of May, 2013 with a fine numerical model for South China. Furthermore, a case of heavy rain that occurred from 8—9 May 2013 over the region from the southwest of Guangdong province to Pearl River Delta is analyzed in detail. Results show that the cold start experiment is not conducive to precipitation 12 hours ahead; the hot start experiment is able to reproduce well the first 6 hours of precipitation, but badly for subsequent prediction; the experiment of assimilating radar-retrieved water vapor is not only able to simulate well the precipitation 6 hours ahead, but also able to correctly predict the evolution of rain bands from 6 to 12 hours in advance.     

周跳探测中一种改进的电离层残差法

高精度GPS定位的核心问题之一是周跳探测,针对电离层残差法不能较好适用于低采样率情形的不足,提出基于站间单差观测值的电离层残差法。在短基线中,利用站间单差较大地消弱电离层的影响,所提方法能弥补电离层残差法不能较好适用于高采样率情形的不足。利用实测数据实验证明,改进的电离层方法在采样间隔为30s时同样适用,可以将周跳显著地分离。