Meteorological Data Acquisition Research Articles

Prediction model of time diversity using Japan rain radar data

SummaryThe effects of rain attenuation on communication systems will become more pronounced in future satellite communication systems, especially with the planned use of the 21‐GHz band or higher‐frequency bands. Diversity techniques provide a solution to mitigate rain attenuation effects. This study proposes a time diversity technique, one such technique that is likely to demonstrate high effectiveness. To model the system, rainfall rate statistics are necessary, and reliability is improved as the amount of statistical data increases. This paper derives the cumulative distribution of the rainfall rate across Japan over 4 years using rain radar data from the automated meteorological data acquisition system and ground‐based rain radar network and evaluates the rainfall rate at 23 observation points across Japan. We carry out a performance evaluation for all locations within Japan to confirm the efficiency of the time diversity method. Finally, we propose prediction model of the time diversity gain for Japan and other significant parameter which is time correlation of rainfall rate that was found from the time diversity results for further investigation. Copyright © 2016 John Wiley & Sons, Ltd.

A Network of Mode-S Receivers for Routine Acquisition of Aircraft-Derived Meteorological Data

AbstractAircraft are an important source of meteorological observations for both numerical weather models and aviation weather forecasting. There has been increasing interest in novel methods for gathering aircraft-based observations, especially mode-selective (Mode-S) enhanced surveillance (EHS)-derived data. This paper reports on the progress made in the United Kingdom at the Met Office on receiving and processing these data. Five receivers have been deployed, providing up to 5.7 million observations of horizontal wind and temperatures per day over the United Kingdom. The receivers are relatively low cost and deploying them at existing operational weather radar sites has been shown to be an ideal choice. Heading corrections are required to improve the quality of the wind observations. When corrected the Mode-S EHS wind data have similar observations-minus-background (o−b) statistics as Aircraft Meteorological Data Relay [AMDAR; using a Met Office version of the Unified Model over the United Kingdom (UKV)]. For the u wind component, the average per model run o−b root-mean-square value for the Mode-S EHS–derived data was 2.45 and 2.12 m s−1 for AMDAR. The AMDAR data are assimilated into the model.

Spatiotemporal Evaluation of the Gauge-Adjusted Global Satellite Mapping of Precipitation at the Basin Scale

This study evaluated the accuracy of gauge-adjusted Global Satellite Mapping of Precipitation (GSMaP_Gauge version V5.222.1, hereafter G_Gauge) data in Japan’s Tone River basin during 2006-2009. Specifically, the accuracy of a gauge non-adjusted product, GSMaP Moving Vector with Kalman Filter (GSMaP_MVK, hereafter G_MVK), was also evaluated. Both products were also evaluated against ground observation data from rain gauge-radar combined product Radar-Automated Meteorological Data Acquisition System (Radar-AMeDAS) in terms of temporal and spatial variability. Temporal analyses showed that G_Gauge had better accuracy than G_MVK at sub-daily time scales (1, 3, 6, 9, 12, and 24 h) within any range of precipitation intensity and better detection capabilities of rainfall event. Linear regressions with Radar-AMeDAS showed better performance for G_Gauge than G_MVK at any time scales in terms of Pearson’s correlation coefficient and the slope of regression. At an hourly scale, in particular, Pearson’s correlation coefficient for G_Gauge (0.84) was higher than that for G_MVK (0.72) as well as the slope of linear regression (0.87 and 0.65, respectively). The probability of detection (POD) improved from 0.48 (G_MVK) to 0.70 (G_Gauge) when gauge-adjusted data were used. However, spatial analysis detected that G_Gauge still underestimated the precipitation intensity in high-elevation regions and slightly overestimated it in low elevation regions. The POD and false alarm ratio had a linear relationship with log-transformed elevation data, and the relationships were stronger in the winter seasons than in the summer seasons. At any spatial and temporal scale, the evaluation of these products should consider seasonal changes (especially in winter) and the topographic effects. For further improvements of G_Gauge, we suggest including higher resolution gauge-based network data than the Climate Prediction Center unified gauge-based analysis of global daily precipitation, which is used for G_Gauge.

1980年代後半の全国的な冬季昇温に伴う降水量分布の変化と気圧配置型の影響

Changes in precipitation distribution associated with a surface temperature rise in the late 1980s, which accompanied a climatic regime shift, are investigated using Automated Meteorological Data Acquisition System (AMeDAS) data of the Japan Meteorological Agency, and their relations with the variability of surface pressure patterns are revealed. After the temperature rise, the frequency of winter monsoon pressure patterns did not decrease. According to the classification of pressure patterns, long-term variations of surface pressure pattern frequencies showed negative relations between the winter monsoon and high-pressure patterns before 1992, which subsequently changed to the negative relations between the winter monsoon and traveling low-pressure systems. After the temperature rise, in years when low-pressure patterns prevailed, precipitation increases were observed in western Japan due to low-pressure systems traveling over the Pacific coast, and in wider areas from central Japan to Kyusyu areas due to low-pressure systems traveling over the Sea of Japan. Recently, the frequency of stationary front patterns has been increasing with precipitation increasing in the Setouchi area of western Japan. In years with a warm winter, precipitation increased in wider areas of the Pacific coast to inland areas of central Japan. In cold winters, low-pressure systems traveling over the Pacific coast decreased precipitation in central to western Japan. However, after a temperature rise, low-pressure systems traveling over the Sea of Japan decreased precipitation at the coast of the sea of Japan from central Japan to Hokkaido.

Hydrologic analysis of a flood based on a new Digital Elevation Model

Abstract. These The present study aims to simulate the hydrologic processes of a flood, based on a new, highly accurate Digital Elevation Model (DEM). The DEM is provided by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) of Japan, and has a spatial resolution of five meters. It was generated by the new National Project in 2012. The Hydrologic Engineering Center - Hydrologic Modeling System (HEC-HMS) is used to simulate the hydrologic process of a flood of the Onga River in Iizuka City, Japan. A large flood event in the typhoon season in 2003 caused serious damage around the Iizuka City area. Precise records of rainfall data from the Automated Meteorological Data Acquisition System (AMeDAS) were input into the HEC-HMS. The estimated flood area of the simulation results by HEC-HMS was identical to the observed flood area. A watershed aggregation map is also generated by HEC-HMS around the Onga River.

Usability of AMeDAS Sunshine Duration Data for Statistical Evaluation of Spatial Average Irradiance Fluctuation Characteristics

SUMMARYIn order to mitigate the impacts of high‐penetration photovoltaic power generation systems (HP‐PVS) on the electric power system operation, the statistical evaluation of the aggregated power output fluctuation characteristics of HP‐PVS is important. By using the multipoint irradiance data observed for a year in the Chubu region of Japan, we have evaluated the fluctuation characteristics of spatial average irradiance. However, the study period is not enough for a statistical evaluation. Therefore, this study assessed the usability of the sunlight duration data of AMeDAS (Automated Meteorological Data Acquisition System) for the statistical evaluation of fluctuation characteristics in terms of the daily maximum fluctuation width in 120 min. The method of irradiance estimation from the sunlight duration data at single point proposed in the preceding study was modified to be suitable for the spatial average irradiance estimation by taking into account the smoothing effect of irradiance fluctuation among several points. The results suggest that the AMeDAS sunlight duration data would be useful for statistical evaluation of the fluctuation characteristics of the spatial average irradiance of an electric power system service area.

<b>Method for Evaluating Train Safety in Case of Strong Winds</b>

This paper proposes a method for evaluating train running safety in strong wind conditions using the probabilities of strong wind occurrence according to wind direction. The Weibull coefficients cd and kd for 16 wind directions were calculated on the basis of data from 10-min maximum instantaneous wind velocities for each wind direction at 772 Automated Meteorological Data Acquisition System (AMeDAS) stations. Probabilities Px of the occurrence of strong winds exceeding the critical wind speeds for overturning were estimated for a train in a virtual railway section by using cd and kd calculated on the basis of the wind data observed at a windy AMeDAS station. Px values were found to vary from 6.2×10-6 to 8.6×10-5 depending on the angle between the traveling direction of the train and each wind direction. The values of Px ranged from 1.4% to 20% of the Py values, which were calculated out of consideration of strong wind occurrence according to wind direction.

INSAT-3D Quality Analysis System (i3dQAS)

Abstract. INSAT-3D, an advanced meteorological satellite of ISRO carrying Imager and Sounder payloads is designed for acquiring data required for detailed climatological applications. At established data centres, Raw (L-0) data is processed to generate systematically corrected (Level-1) and geo-physical (Level-2) products which are further disseminated for use in climate related studies. Data quality evaluation (DQE) of basic data products of INSAT-3D is being operationally carried out at MOSDAC, Ahmedabad to monitor in-orbit sensor health, quantify data quality and provide feedback to various missions teams for corrective actions. DQE methodology and quality parameters have been defined keeping in view repeatability of data acquisition and quality requirements of meteorological data. In this paper, we have described INSAT-3D Quality Analysis System (i3dQAS) designed to facilitate effective data quality monitoring through web based portal. Overall context of i3dQAS in a typical data centre set-up, major objectives and design aspects to highlight the architectural and functional view of system are described. Utility of i3dQAS for mission monitoring is described through analysis scenarios for monitoring payload health and geometric accuracy of Imager.

Atmospheric Data Collection, Processing and Database Management in India Meteorological Department

The availability of a proper meteorological database is a major prerequisite for studying the processes of climate by scientists and policy makers. The acquisition of pertinent meteorological data, timely access and database management are important components that make the climate information valuable. New technologies in the field of communication and great strides in the automation age have offered new ways of making data products available to the user community. Data collection and database management are the key components of the availability of climate data. Due to increased observation frequency, huge amounts of data are received at data centres. Fast and effective quality control for identification and flagging of suspicious observations is needed at the data centres to provide easy access to information and dissemination of quality assured observations to the users. India Meteorological Department (IMD) collects, processes, archives and disseminates a wide range of weather, climate and other environmental data generated by the department’s observational network.With the installation of ‘CliSys’ Climate Database Management System (CDMS) in the National Data Centre located at Pune, the data acquisition and processing operations have been automated. This system provides a set of tools and procedures that allow all data relevant to climate studies to be properly stored and managed. It serves the main objectives of climate data collection, storage, quality control, easy access, data protection, climate data analysis and customized product generation.

Development of the automatic system of the “Vostochnyi” cosmodrome weather support

A complex system of the operational acquisition, processing, and presentation of meteorological data is developed according to the requirements to cosmodrome weather support. The proposed system allows for the high efficiency of space rocket launches by making prompt decisions based on the information provided by the weather support system.

An Ensemble Downscaling Prediction Experiment for Medium-Range Forecast of the Daily Mean Surface Temperature Distribution over Northeastern Japan during Summer

To assess medium-range forecasts of detailed spatial distributions of the daily mean temperature, an ensemble downscaling forecast experiment was conducted using the Japan Meteorological Agency (JMA) nonhydrostatic model (NHM) with horizontal resolutions of 25 km and 5 km. Special attention was paid to the anomalously cool summers over northeastern Japan caused by northeasterly winds called Yamase. The results are validated against the daily mean surface temperatures observed by the Automated Meteorological Data Acquisition System (AMeDAS) in the study area. Ensemble mean downscaling forecasts can successfully extract reliable signals with information about local circulations. The ensemble mean forecasts reduce the root mean square errors of the daily mean surface temperature by 15 % compared to single downscaling forecasts. The ensemble spreads also indicate the possibility of making probabilistic predictions that consider the effects of local circulations in addition to large-scale motions. The ensemble downscaling forecasts have 80 % larger spreads than the global forecasts with the JMA global spectral model at a resolution TL159L60 and approach the theoretical value. An empirical orthogonal function (EOF) analysis indicates that the predictability depends on the EOF modes. The predictable periods are 8 days for the homogeneous mode over northeastern Japan, 5 days for the Yamase mode (east-west mode), and 2 days for the north-south mode. The dynamical downscaling can properly predict the amplitudes of the EOF modes. In particular, the dynamical downscaling can predict 90 % of the Yamase mode, as compared to 20 % prediction of the global model for the same mode.

稠密観測データに基づく晴天弱風の冬季夜間における東京都区部を中心とした気温分布について

Tokyo—one of the largest cities in the world—exhibits intensive urban land use, urban sprawl, and high anthropogenic heat exhaustion, which produce characteristic urban temperature distributions. Typical features of the nocturnal temperature distribution from November to February under conditions of clear skies and weak winds were analyzed for the Tokyo metropolitan-ward area using data from spatially high-density observations from the Automated Meteorological Data Acquisition System (AMeDAS) of the Japan Meteorological Agency (JMA), municipal air pollution monitoring systems, and Extended-METROS from 2006/2007 to 2009/2010. To analyze the structure of temperature distributions in the Tokyo-ward area, hourly temperature data at 124 stations were interpolated into grid points with 1-km intervals. When high temperatures in central Tokyo were expressed as a difference in AMeDAS temperature between central Tokyo (Otemachi) and an average of four points outside the Tokyo-ward area, the weather conditions most strongly affecting this temperature difference at 06:00 Japan Standard Time (JST), prior to sunrise, were cloud amount followed by wind speed. The temperature difference at night under clear-sky and weak-wind conditions (average cloud amount of 2/10 or less and average wind speed of 3m/s or less) generally showed an abrupt increase during the several hours before and after sunset followed by a gradual increase, reaching maximum levels before sunrise (06:00 JST). When the temperature difference before sunrise was large, the difference would evidently increase even after midnight; however, if this difference was small, it would tend to decrease after midnight. The high temperatures in the metropolitan area were concentrated throughout the night near the southern area of Chuo ward. In particular, it is noted that several zones of steep horizontal temperature gradients were detected in the metropolitan-ward area. These zones (e.g. starting from the southern part of Saitama Prefecture, it appeared through the border between Nerima and Itabashi wards, Toshima, Shinjuku, and the area stretching from western Setagaya to the southwest) appeared during the period several hours before and after sunset, and gradually became more noticeable near sunrise. The distribution of temperature-decrease rate around sunset also showed steep horizontal gradient zones, which corresponded to regions exhibiting steep horizontal temperature gradient zones between the inner city and outer area.

Usability of AMeDAS Sunshine Duration Data for Statistical Evaluation of Spatial Average Irradiance Fluctuation Characteristics

SUMMARY In order to mitigate the impacts of high-penetration photovoltaic power generation systems (HP-PVS) on the electric power system operation, the statistical evaluation of the aggregated power output fluctuation characteristics of HP-PVS is important. By using the multipoint irradiance data observed for a year in the Chubu region of Japan, we have evaluated the fluctuation characteristics of spatial average irradiance. However, the study period is not enough for a statistical evaluation. Therefore, this study assessed the usability of the sunlight duration data of AMeDAS (Automated Meteorological Data Acquisition System) for the statistical evaluation of fluctuation characteristics in terms of the daily maximum fluctuation width in 120 min. The method of irradiance estimation from the sunlight duration data at single point proposed in the preceding study was modified to be suitable for the spatial average irradiance estimation by taking into account the smoothing effect of irradiance fluctuation among several points. The results suggest that the AMeDAS sunlight duration data would be useful for statistical evaluation of the fluctuation characteristics of the spatial average irradiance of an electric power system service area.

Design of a Microcontroller-Based Data Acquisition System for Ground Weather Observations: Evaluation of Radio Refractivity of Air

A meteorological data acquisition system is built using a PIC16F877A microcontroller and electric output-based sensors. This system is programmed in C language using the PCWH compiler. It is smart, accurate, cheap, small, light and easily movable. It is designed to automatically get instantaneous measurements of air temperature, atmospheric pressure, and relative humidity. Depending on their utilisation, these measurements are collected with repetition rate tuneable from one minute to one hour. They are displayed on LCD screen and transferred to a personal computer where they are stored and processed. As an application, such data are recorded in situ and used to estimate the radio refractivity of air near the ground in real time. This parameter is necessary to account for the propagation of radiofrequency waves through the lower atmosphere, during wireless transmissions.

The Role of GPS Precipitable Water Vapor and Atmosphere Stability Index in the Statistically Based Rainfall Estimation Using MTSAT Data

Abstract A rainfall estimation method was developed based on the statistical relationships between cloud-top temperature and rainfall rates acquired by both the 10.8-μm channel of the Multi-Functional Transport Satellite (MTSAT) series and the Automated Meteorological Data Acquisition System (AMeDAS) C-band radar, respectively. The method focused on cumulonimbus (Cb) clouds and was developed in the period of June–September 2010 and 2011 over the landmass of Japan and its surrounding area. Total precipitable water vapor (PWV) and atmospheric vertical instability were considered to represent the atmospheric environmental conditions during the development of statistical models. Validations were performed by comparing the estimated values with the observed rainfall derived from the AMeDAS rain gauge network and the Tropical Rainfall Measuring Mission (TRMM) 3B42 rainfall estimation product. The results demonstrated that the models that considered the combination of total PWV and atmospheric vertical instability were relatively more sensitive to heavy rainfall than were the models that considered no atmospheric environmental conditions. The use of such combined information indicated a reasonable improvement, especially in terms of the correlation between estimated and observed rainfall. Intercomparison results with the TRMM 3B42 confirmed that MTSAT-based rainfall estimations made by considering atmospheric environmental conditions were more accurate for estimating rainfall generated by Cb cloud.

Gully Erosion Study and Control: A Case Study of Queen Ede Gully in Benin City

This paper presents findings from studies carried out on the Queen Ede gully erosion site in Benin City, in the south-southern zone of Nigeria. The studies involved detailed topographical, geotechnical, meteorological and hydrological data acquisition. The data were processed and analyzed to determine catchment size, gully morphology, soil characteristics, rainfall pattern and hydrological pattern. These were then interpreted and used to determine the method of control to be adopted. The adopted control measures is a combination of structural and non-structural methods. The structural method involved the use of gully control structures to divert the runoff entering the gully from the head, while the non-structural method involved the use of boulders and vegetation to stabilize the gully walls around the head region.

Aspectos Hidrodinâmicos, Balanço Hídrico e Simulação de Fluxo no Aquífero Costeiro de Itaipuaçu, Maricá – Rio de Janeiro, Brasil

This research was conducted in the coastal aquifer of Itaipuaçu district, Marica, Rio de Janeiro in Brazil. This is an aquifer of great importance for the region, as it is still the only autochthonous means of water supply for a growing population. The use of this water resource without control is a big problem, because quality can be impaired by contamination coming from the surface and, as a coastal aquifer, overexploitation can generate migration of saltwater / freshwater interface towards mainland and can salinize it. The paper aims to present the hydrodynamic characteristics of the shallow aquifer of the study area, by assessing local flow, flow parameters of the aquifer, acquisition and processing of meteorological data and water balance of the aquifer system, with the application of Visual Balan V.2.0 code. Other calculation methodologies were employed, as hydrometeorological simplified balance (Easybal v.4 computer code) and water balance with use of Darcy's Law. Wells were drilled in the shallow aquifer of the study area to assess local stratigraphy, and interference tests were performed to obtain physical parameters of the aquifer (permeability and storage coefficient). In situ measurements of water levels in wells were performed in the region to map the shallow aquifer head distribution. The data indicate a low hydraulic gradient and equipotential lines subparallel to the shoreline. Based on the hydraulic parameters, flow simulations were performed with the software Visual Modflow 4.2. The results obtained to date indicate a recharge of about 36% of the precipitation and hydraulic gradient less than 1%. Obtaining in situ parameters of the aquifer was crucial for the proper model fit and evaluation of the local aquifer properties.

Effects of Synoptic-Scale Wind under the Typical Summer Pressure Pattern on the Mesoscale High-Temperature Events in the Osaka and Kyoto Urban Areas by the WRF Model

AbstractThe actual conditions of mesoscale summer high temperatures (HTs) recorded in the Osaka–Kyoto urban area of Japan were investigated using an observation network. The daytime temperatures observed on 10 HT events in this area were the highest in the southern area of Kyoto [area with no Automated Meteorological Data Acquisition System (AMeDAS) observation sites]. To quantitatively evaluate the formation mechanisms of HT events, a heat budget analysis on an atmospheric column was conducted using the Weather Research and Forecasting (WRF) model. The results showed that over the HT area the daytime column temperature increased as a result of sensible-heat diffusion generated from the urban surface at the contribution rate of 54% and as a result of the sensible-heat advection and diffusion supplied from the sides and at the top of the column at the rate of 46% of all sensible heat supplied. To clarify previously unreported effects of synoptic-scale winds under typical summer pressure patterns on the HT events, a sensitivity experiment with no surface heat fluxes, backward trajectory analysis, and Euler forward tracer analysis was performed. These analyses yielded the following findings: 1) sensible heat at the synoptic scale and/or mesoscale was transported from the tropics by circulation patterns along the edge of the Pacific high as well as from tropical cyclones that were present in the vicinity of Japan and 2) airflow over the Kii Mountains also contributes to the HT events.

High‐resolution prediction of leaf onset date in Japan in the 21st century under the IPCC A1B scenario

Reports indicate that leaf onset (leaf flush) of deciduous trees in cool-temperate ecosystems is occurring earlier in the spring in response to global warming. In this study, we created two types of phenology models, one driven only by warmth (spring warming [SW] model) and another driven by both warmth and winter chilling (parallel chill [PC] model), to predict such phenomena in the Japanese Islands at high spatial resolution (500 m). We calibrated these models using leaf onset dates derived from satellite data (Terra/MODIS) and in situ temperature data derived from a dense network of ground stations Automated Meteorological Data Acquisition System. We ran the model using future climate predictions created by the Japanese Meteorological Agency's MRI-AGCM3.1S model. In comparison to the first decade of the 2000s, our results predict that the date of leaf onset in the 2030s will advance by an average of 12 days under the SW model and 7 days under the PC model throughout the study area. The date of onset in the 2090s will advance by 26 days under the SW model and by 15 days under the PC model. The greatest impact will occur on Hokkaido (the northernmost island) and in the central mountains.

Involvement of magnitude of ambient temperature change in nonspecific effect in perceived placebo effect on lower urinary tract symptoms: study on switching of naftopidil in patients with benign prostatic hyperplasia

PurposeTo determine if switching from one brand of the α1-adrenoceptor antagonist naftopidil (Avishot™) to another brand (Flivas™) under the same conditions causes the same changes in lower urinary tract symptoms (LUTS) and quality of life (QOL) as the perceived placebo effect, and if ambient temperature as a nonspecific factor is related to those changes in benign prostatic hyperplasia (BPH) patients.Patients and methodsA retrospective study was carried out on 217 BPH patients who had received Avishot™ for more than 6 months and then were switched to Flivas™ at the same dose and timing. The two drugs contain the same principal ingredient and display the same pharmacokinetic properties. The International Prostate Symptom Score (IPSS), QOL score, and average monthly ambient temperature at the patients’ residence area from the Automated Meteorological Data Acquisition System in Japan were used for the evaluation.ResultsA significant change in urinary storage symptoms (P = 0.006), and especially in nighttime frequency (P< 0.001), was observed by switching drugs, suggesting the perceived placebo effect. There was significant improvement of daytime frequency (P< 0.05), nighttime frequency (P< 0.001), storage symptoms (P< 0.001), and total IPSS (P< 0.05) when the magnitude of ambient temperature change from before and 3 months after switching drugs was higher than 10°C, while no significant improvement was noted in any of the parameters examined when the same was lower than 10°C.ConclusionThe present study showed the nonspecific effect of magnitude of ambient temperature change was involved in the perceived placebo effect on LUTS, especially on storage symptoms, by switching drugs. The nonspecific effect on LUTS with BPH needs to be considered when evaluating subjective treatment efficacy of drugs for LUTS with BPH in routine clinical practice. The present study supports the lifestyle advice “avoid exposing the lower body to cold temperature” or “keep warm when it is cold” for LUTS with BPH.