Use of Dual Polarization Radar in Validation of Satellite Precipitation Measurements: Rationale and Opportunities

Dual-polarization weather radars have evolved significantly in the last three decades culminating in the operational deployment by the National Weather Service. In addition to operational applications in the weather service, dual-polarization radars have shown significant potential in contributing to the research fields of ground based remote sensing of rainfall microphysics, study of precipitation evolution and hydrometeor classification. Furthermore the dual-polarization radars have also raised the awareness of radar system aspects such as calibration. Microphysical characterization of precipitation and quantitative precipitation estimation are important applications that are critical in the validation of satellite borne precipitation measurements and also serves as a valuable tool in algorithm development. This paper presents the important role played by dual-polarization radar in validating space borne precipitation measurements. Starting from a historical evolution, the various configurations of dual-polarization radar are presented. Examples of raindrop size distribution retrievals and hydrometeor type classification are discussed. The quantitative precipitation estimation is a product of direct relevance to space borne observations. During the TRMM program substantial advancement was made with ground based polarization radars specially collecting unique observations in the tropics which are noted. The scientific accomplishments of relevance to space borne measurements of precipitation are summarized. The potential of dual-polarization radars and opportunities in the era of global precipitation measurement mission is also discussed

Microphysical Properties of Frozen Particles Inferred from Global Precipitation Measurement (GPM) Microwave Imager (GMI) Polarimetric Measurements

Scattering differences induced by frozen particle microphysical properties are investigated, using the vertically (V) and horizontally (H) polarized radiances from the Global Precipitation Measurement (GPM) Microwave Imager (GMI) 89 and 166GHz channels. It is the first study on global frozen particle microphysical properties that uses the dual-frequency microwave polarimetric signals. From the ice cloud scenes identified by the 183.3 3GHz channel brightness temperature (TB), we find that the scatterings of frozen particles are highly polarized with V-H polarimetric differences (PD) being positive throughout the tropics and the winter hemisphere mid-latitude jet regions, including PDs from the GMI 89 and 166GHz TBs, as well as the PD at 640GHz from the ER-2 Compact Scanning Submillimeter-wave Imaging Radiometer (CoSSIR) during the TC4 campaign. Large polarization dominantly occurs mostly near convective outflow region (i.e., anvils or stratiform precipitation), while the polarization signal is small inside deep convective cores as well as at the remote cirrus region. Neglecting the polarimetric signal would result in as large as 30 error in ice water path retrievals. There is a universal bell-curve in the PD TB relationship, where the PD amplitude peaks at 10K for all three channels in the tropics and increases slightly with latitude. Moreover, the 166GHz PD tends to increase in the case where a melting layer is beneath the frozen particles aloft in the atmosphere, while 89GHz PD is less sensitive than 166GHz to the melting layer. This property creates a unique PD feature for the identification of the melting layer and stratiform rain with passive sensors. Horizontally oriented non-spherical frozen particles are thought to produce the observed PD because of different ice scattering properties in the V and H polarizations. On the other hand, changes in the ice microphysical habitats or orientation due to turbulence mixing can also lead to a reduced PD in the deep convective cores. The current GMI polarimetric measurements themselves cannot fully disentangle the possible mechanisms

Doctor of Philosophy

dissertationThis study attempts to characterize the particular convection type, namely storm morphologies, convective properties, and microphysics, of different weather regimes within the East Asian Summer Monsoon (EASM). Defined rain bands and associated rainfall characteristics are examined in terms of population, location, variability, and rainfall frequency. Though the Mei-Yu rain bands produce a relatively large rain belt over South China and Taiwan during mid-May to mid-June, and over the Yangtze River region during mid-June to mid-July, rainfall maxima and heavy precipitation are most frequent over specific locations. Generally, the frequency of storms with high echo tops, significant convection, and evident ice scattering signature is greatest in post-Meiyu and break periods, less so during the active Mei-Yu, and least frequent before the monsoon onset. However, preseason, as well as break periods, has a larger fraction of intense convection that behaves more like the classic continental tropical convection with major ice-based rainfall processes. Specifically, preseason and break periods have a larger fraction of rainfall contributed from storms with a 40-dBZ convective core extending above 7-8 km. By comparison, active Mei-Yu convection more closely resembles classic tropical maritime convection with relatively more importance of "warm-rain" collision and coalescence processes with weaker convection but heavy precipitation. Monsoon precipitation over the Yangtze River region, though having similar size and cloud top, differs from its counterpart in South China on convective properties, vertical structures, and rainfall contribution by storm types. Based on Tropical Rainfall Measuring Mission (TRMM) climatology, the EASM is comparable to other monsoon regimes by having convective properties intermediate between the intense convective systems over continents, and the weaker convective systems found in the classic maritime precipitation regimes. Analysis based on Terrain-influenced Monsoon Rainfall Experiment (TiMREX) observations indicates that most of the heavy rainfall is associated with Mei-Yu rain bands, strongly influenced by upstream low-level jets, unstable upstream conditions, but a more nearly moist neutral storm environment. A particular long-duration heavy precipitation event is analyzed in detail, and features continuous development of "back-building" new convection under the influence of an extensive precipitation-created cold pool and substantial orography downstream

Remote Sensing of the Oceans

This book covers different topics in the framework of remote sensing of the oceans. Latest research advancements and brand-new studies are presented that address the exploitation of remote sensing instruments and simulation tools to improve the understanding of ocean processes and enable cutting-edge applications with the aim of preserving the ocean environment and supporting the blue economy. Hence, this book provides a reference framework for state-of-the-art remote sensing methods that deal with the generation of added-value products and the geophysical information retrieval in related fields, including: Oil spill detection and discrimination; Analysis of tropical cyclones and sea echoes; Shoreline and aquaculture area extraction; Monitoring coastal marine litter and moving vessels; Processing of SAR, HF radar and UAV measurements

Earth resources: A continuing bibliography with indexes (issue 62)

This bibliography lists 544 reports, articles, and other documents introduced into the NASA scientific and technical information system between April 1 and June 30, 1989. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economic analysis

Proceedings Of The 18th Annual Meeting Of The Asia Oceania Geosciences Society (Aogs 2021)

The 18th Annual Meeting of the Asia Oceania Geosciences Society (AOGS 2021) was held from 1st to 6th August 2021. This proceedings volume includes selected extended abstracts from a challenging array of presentations at this conference. The AOGS Annual Meeting is a leading venue for professional interaction among researchers and practitioners, covering diverse disciplines of geosciences

Remote Sensing in Mangroves

The book highlights recent advancements in the mapping and monitoring of mangrove forests using earth observation satellite data. New and historical satellite data and aerial photographs have been used to map the extent, change and bio-physical parameters, such as phenology and biomass. Research was conducted in different parts of the world. Knowledge and understanding gained from this book can be used for the sustainable management of mangrove forests of the worl

위성관측과 수치실험에서 본 한반도 집중호우 특성

학위논문 (박사)-- 서울대학교 대학원 : 지구환경과학부, 2015. 8. 손병주.In order to objectively classify heavy rain types over East Asia during the summer, K-means clustering was applied to the Tropical Rainfall Measuring System (TRMM) Precipitation Radar (PR) reflectivity profiles. Two main types of heavy rainfall were emerged: a well-developed deep convective system that is situated predominantly over mainland China (Type 1, cold type) and a medium-depth rain system that is mostly found in the oceanic region over the western periphery of the North Pacific high (Type 2, warm type). It is noted that Type 1 propagates eastward from mainland China toward the area including Korea and Japan whereas Type 2 expands northward with the progress of summer. Such different temporal evolution appears to bring in the coexistence of two rain types of heavy rainfall over the Korean peninsula. This study further examines the spatio-temporal evolution of cloud systems and thermodynamic/dynamic features associated with heavy rainfall types over the Korean peninsula using geostationary satellites and reanalysis data, respectively. It was revealed that the cold type is characterized by an eastward-moving oval-shaped cloud system, while the warm type is represented by a northeastward-moving broader system. The cold-type heavy rainfall was usually associated with a local cloud system induced by convective instability. In contrast, the large-scale synoptic forcings (i.e., low-level moisture convergence and high-level divergence) under moist-adiabatically near-neutral conditions are thought to facilitate the possibility of warm-type heavy rainfall over the Korean peninsula. Collision and coalescence processes in the lower cloud layer appear to be responsible cloud microphysics for forming heavy rainfall there. In order to examine whether the numerical experiments could provide evidences supporting the hypothesis of causing the warm-type as well as cold-type heavy rainfall, numerical experiments were taken with ideally prescribed thermodynamic conditions. Under the prescribed moist-adiabatically near-neutral conditions, the warm-type simulation results in a lower storm height, earlier onset of precipitation, and heavier precipitation through collision-coalescence process below the melting layer. The lack of upper-level snow and close interaction between super-cooled raindrops and ice particles at the initial stage were also noted in the warm-type experiment. In contrast, the growth of snow and graupel particles and melting process of ice particles appear to be responsible for the cold-type heavy rainfall. In real-case simulations, Double Moment 6-class (WDM6) scheme simulated the most realistic vertical structure of summertime heavy rainfall over the Korean peninsula among eight Weather and Research Forecasting (WRF) microphysics schemes by virtue of the smallest amount of snow and modified warm-rain physics. However, excessive graupel in the WDM6 scheme was thought to be a problem. In addition, a warm-type heavy rain event was reasonably simulated using the WRF model, implying the importance of large-scale environmental setup in the prediction of warm-type heavy rainfall. Therefore, improvement of microphysical parameterization based on observations and a better large-scale environment are thought to be important factors for enhancing the predictability of warm-type heavy rainfall over the Korean peninsula in the humid East Asian summer environment.Abstract i Table of Contents iii Lists of Figures iv 1. Introduction １ 2. Satellite observation ８ 2.1. Data and method ８ 2.2. East Asia １３ 2.2.1. Heavy rainfall type classification １３ 2.2.2. Seasonal evolution ２３ 2.2.3. Diurnal cycle ２７ 2.2.4. Environmental conditions ３０ 2.3. Korea ３４ 2.3.1. Cold-type heavy rainfall event ３５ 2.3.2. Warm-type heavy rainfall event ４１ 2.3.3. Cloud pattern composite ４７ 2.3.4. Synoptic environment composite ５０ 2.4. Conclusions ６５ 2.5. Additional statistics ６８ 2.5.1. Seasonal evolution (+September) ６８ 2.5.2. Influence of typhoon ７１ 2.5.3. Tropical distribution ７４ 3. Numerical experiments ７７ 3.1. Idealized simulation ７７ 3.1.1. Model setup ７８ 3.1.2. Storm evolution ７９ 3.1.3. Effect of wind shear ９７ 3.2. Real case simulation １０４ 3.2.1. Methodology １０６ 3.2.2. Comparison result １１１ 3.2.3. Discussion １２３ 3.3. Case study １２７ 3.4. Conclusions １３６ References １３９ 국문초록 １５１ 감사의 글 １５３Docto