Estimation of flow enhancement in the Kinneret watershed due to cloud seeding

A comparison is carried out between historical records of the flow measured in Kinneret watershed during and prior to the time of cloud seeding for rainfall enhancement. Precipitation series for the control area of the meteorological experimentation serve as a reference for the comparison. The fluctuations of the flow, which would have occurred unless the effect of the seeding, are estimated by a linear regression on the precipitation as the control. The regression parameters are calibrated separately for the unseeded and for the seeded time series. The model with the parameters calibrated for the unseeded series is applied on the rainfall recorded during the seeded time, and vice versa. The difference between the measured and the computed data is attributed to the effect of cloud seeding. Similar comparisons are carried out with respect to rainfall series recorded at the target area and at the edge of the enhanced area.The results indicate that the flow from the affected sector of the watershed has been enhanced, with respect to the control, by 31×10⁶ m ³/year, at a significance level of 31. This enhancement is 5% of the volume which is generated in that area. The rates found with respect to the rainfall at the edge are higher than those found with respect to the control, while those with respect to the rainfall at the center of the target area are lower.     

Research Status and Progress of Balloon-borne Cloud and Precipitation Particles Probe

The accurate observation of the microphysical structure of cloud and precipitation plays an important role in understanding the formation of clouds and precipitation. In-situ measurement using measuring instruments carried by meteorological balloons is an effective way to obtain the microphysical properties of cloud and precipitation particles, which is a supplementary means for aircraft to observe cloud and precipitation particles. This observation method plays a more and more important role in in-situ measurement. According to the difference of the working principle of the existing balloon-borne cloud and precipitation particles probes, the detectors can be divided into particle impact-sampling sensors, particle imaging sensors, light-scattering sensors, light intensity attenuation sensors and charge measurement sensors. The working principles, key technologies and main advantages and disadvantages of typical instruments were summarized, and their applications to detailed cloud structure acquisition, cloud remote sensing method establishment, cloud and precipitation physical process research and parameterization, and scientific observation of thunderstorm clouds were briefly introduced. Finally, the development trend of balloon-borne cloud precipitation particle detectors was prospected, which will provide reference for related technical research and equipment development.     

Cloud tracking using satellite data for predicting the probability of heavy rainfall events in the Mediterranean area

The use of cloud tracking techniques and storm identification procedures is proposed in this paper with the aim of predicting the evolution of cloud entities associated with the highest rainfall probability within a given meteorological scenario. Suitable algorithms for this kind of analysis are based on the processing of digital images in the thermal infrared (IR) band from geostationary satellites: a selection of such algorithms is described in some detail together with a few real case applications. Three heavy rainfall events have been selected for this purpose with reference to the extreme meteorological situation observed during Fall 1992 and 1993 over the Mediterranean area. A window from 30 to 60 °N and from 20 °W to 30 °E has been identified for the analysis of data from the radiometer on board the ESA Meteosat platform. In conclusion, the suitability of cloud tracking techniques for predicting the probability of heavy rainfall events is discussed provided that the former are associated with proper modeling of small scale rainfall distribution.     

地震定位研究及应用综述

地震定位是地震学中最经典、最基本的问题之一，提高定位精度也一直是地震学应用研究的重要课题之一。本文就目前各种地震定位方法进行了大体分类并概述了基本原理及其应用，介绍了目前在国内各实时地震观测系统中应用的台网定位方法，同时将部分台网方法应用于黑龙江省绥棱爆破的定位。     

云顶充满度的特征分析

本文采用GMS－5红外云母，提取了一个描述云顶结构特征的参数一云顶充满度VS。结合地面观测资料，引入了云高参数DTS，得到并分析了参数VS随云高DTS的分布特征，同时还讨论了VS的天气学意义。     

计算机图像处理可视化软件设计与实现

对数字图像实施处理的可视化表达，将使复杂，深奥的图像处理原理更容易理解，文中在详细分析数字图像处理有关理论，算法的基础上，设计了软件的总体框架，实现了多种图像处理功能，并辅以强大的联机帮助。     

Maximum likelihood environmental calibration and the compute program WACALIB a correction

A recently discovered error in the part of the computer program WACALIB that implements maximum likelihood (ML) calibration has been discovered and corrected. The new version of WACALIB has been re-run with all the data-sets from which results based on the earlier version of WACALIB had been published. The new results suggest that ML regression and calibration perform as well or even better than weighted averaging (WA), at least when judged by the apparent root mean squared error. Further work involving cross-validation is required to evaluate more fully the relative performance of WA and ML approaches.     

叠前正演模拟与偏移的网络并行计算

在叠前深度偏移和非零炮检距声波方程正演计算过程中包含了大量的可并行计算的成分。作者在本文中提出叠前正演模拟与偏移的网络并行计算算法，并基于TCP／IP协议，将该算法设计成网络并行处理程序，极大地提高了计算效率。实际运算结果证明，本文提出的并行算法和技术路线是切实可行的。     

Influence of Clouds on UV Irradiance at Ground Level and Backscattered Exittance

The influence of various cloud parameters and the interactions with the ground albedo and the solar zenith angle have been studied by means of model simulations. The radiative transfer model suitable for a cloudy atmosphere as well as for a clear atmosphere has been developed on the basis of the Discrete Ordinate Method. This study leads to a general understanding for cloudy atmospheres: in the presence of a uniform cloud, the cloud scattering is dominant to molecular and aerosol scattering, and it is also wavelength-independent; the ratio of transmitted irradiance in a cloudy atmosphere to that in the background clear atmosphere is independent of cloud height and solar zenith angle. That’s to say, the radiation downwelling out of a cloud is quite isotropic; it decreases approximately exponentially with the cloud optical depth at a rate related to the ground albedo; the reflected irradiance at the top of the atmosphere is dependent on cloud optical depth as well as on solar zenith angle, but not on ground albedo for clouds of not very thin optical depth.     

Large-sample hydrology: recent progress,guidelines for new datasets and grand challenges

ABSTRACT

Large-sample hydrology (LSH) relies on data from large sets (tens to thousands) of catchments to go beyond individual case studies and derive robust conclusions on hydrological processes and models. Numerous LSH datasets have recently been released, covering a wide range of regions and relying on increasingly diverse data sources to characterize catchment behaviour. These datasets offer novel opportunities, yet they are also limited by their lack of comparability, uncertainty estimates and characterization of human impacts. This article (i) underscores the key role of LSH datasets in hydrological studies, (ii) provides a review of currently available LSH datasets, (iii) highlights current limitations of LSH datasets and (iv) proposes guidelines and coordinated actions to overcome these limitations. These guidelines and actions aim to standardize and automatize the creation of LSH datasets worldwide, and to enhance the reproducibility and comparability of hydrological studies.