论文总字数：41464字

目 录

摘要 1

ABSTRACT................................................................................................2

1引言..........................................................................................................3

1.1选题的目的及意义..............................................................................................................3

1.2国内外研究现状..................................................................................................................3

1.3研究内容..............................................................................................................................4

2衰减订正理论基础................................................................................4

2.1双偏振雷达相关参数介绍.................................................................................................5

2.1.1 反射率因子Z..........................................................................................................5

2.1.2 双程差示传播相位变量Φ_DP...................................................................................6

2.1.3 差示传播相位常数K_DP..........................................................................................6

2.2衰减原理.............................................................................................................................6

2.3衰减订正方法……………………………………………………………………….........7

2.3.1 K_DP订正法……………………………………………………………………......7

2.3.2 Z_H-K_DP综合订正法…………………………………………………………...…..8

3衰减订正数据处理试验.........................................................................9

3.1初始数据分析....................................................................................................................9

3.1.1原始Z数据分析………………………………………….....................................10

3.1.2原始 K_DP与Φ_DP数据分析……………………….....………………….………...10

3.2数据预处理........................................................................................................................11

3.2.1 Φ_DP滤波处理……………………………………………………………..............11

3.2.2 K_DP滤波处理………………………………………………………………..........12

3.3衰减订正处理....................................................................................................................13

3.3.1 K_DP法订正..............................................................................................................13

3.3.2 Z_H-K_DP法综合订正法............................................................................................14

4总结与展望...........................................................................................15

参考文献..................................................................................................16

致谢..........................................................................................................17

C波段双偏振雷达反射率因子的衰减订正

林琳

, china

Abstract: Since 1960, double polarization in the field of weather radar research and application has been rapid development. Weather radar in the detection of precipitation, due to weather targets (clouds, raindrops, etc.) on the radar launch electromagnetic waves will have a strong absorption and scattering effect, the radar echo in the precipitation area will occur attenuation, the degree of attenuation and radar emission Wavelength, the shorter the wavelength, the stronger the attenuation. In this paper, based on the study of the principle of attenuation, the classification of several attenuation methods have been proposed, and Nanjing University of Information Science and Technology of the C-band dual-polarization radar, for example, a comprehensive analysis of June 2015 Nanjing heavy rainfall The attenuation and correction of the reflection factor are studied and compared with the data of the closest time Longwangshan S-band radar to verify the attenuation and correction effect. Finally, the advantages and disadvantages of different methods are discussed and analyzed.

Keywords: C - band, double polarization, attenuation correction, reflection factor

1 引言

1.1选题的目的和意义

随着计算机技术日渐成熟，气象雷达作为新型的探测工具，起着愈加重要的作用，尤其是在预报天气灾害和定量估计降水强度等方面。雷达探测降水时，以雷达为中心可以探查到较远的地域，同时获取该地区的实时降水量^[1]，但雷达接收到的回波强度与降水粒子以及大气状况都有关。据统计可得，降水的多少和雷达接收到的反射率因子相关^[2]，但气象雷达进行降水探测时雷达回波经过降水区会受到不同程度的衰减，测得的降水量会偏低，若雷达发射的电磁波波长较短，衰减尤为严重，可能导致雷达获取的回波图像完全失真。因此接收到的回波数据需要通过适当的衰减订正方法进行处理，以获得准确的回波数据及图像，继而估算出降雨量。

随着雷达系统日趋完善，人们大规模地将双偏振雷达运用到预报灾害以及气象科研中^[3]。与普通的多普勒天气雷达相比，双偏振多普勒雷达可以交替或同时发射并接收水平竖直两种偏振波的信号，估测到的降水量精度较高^[4]。双线偏振雷达不仅可以获取回波强度、径向速度和谱宽等基本参量，还可以提供水平和垂直回波的强度以及相位变化等偏振参量（差分反射率因子Z_DR、差分传播相移Φ_DP、差分传播相移率K_DP等），并且在估测地区降水量时，可获取9个仰角的数据及图像。若继续阐述研讨上述参数，进一步鉴定降水粒子的形状、大小、状态、空间分布及降水类型等更为具体的信息，就有可能探查不同相态（混合型）降水的比例和降水粒子类型^[5]。正是由于前文提及的各方面优势，多普勒偏振雷达的发展显得愈加重要。

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