Satellite Cloud Pictures Research Articles

Tropospheric formaldehyde levels infer ambient formaldehyde-induced brain diseases and global burden in China, 2013–2019

Although air pollutions cause human diseases, no epidemiological study has investigated the effect of exposure to air pollutants on brain diseases in the general population. Our objective was to examine the association between tropospheric airborne pollutants and human health risk and global burden, especially, attributable to indoor formaldehyde (FA) pollution in China. The data of tropospheric pollutants, such as: CO, NO, O3, PM2.5 or PM10, SO2, and FA in China, 2013–2019, which were derived from the database of satellite remote-sensing, were first calculated and then analyzed them according to satellite cloud pictures. The rate of prevalence, incidence, deaths, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) of the Chinese population was obtained from the Global Burden of Diseases (GBD 2010). A linear regression analysis was used to evaluate the relationship between tropospheric FA concentrations and GBD indexes of human brain diseases, the numbers of fire plot, the average summer temperature, population density and car sales in China from 2013 to 2019. Our results showed that the levels of tropospheric FA could reflect the degree of indoor air FA pollution on a nationwide scale in China; in particular, only tropospheric FA exhibited a positive correlation with the rates of both prevalence and YLDs in brain diseases including: Alzheimer's disease (AD) and brain cancer, but not in Parkinson's disease and depression. In particular, the spatial-temporal changes in tropospheric FA levels were consistent with the geographical distribution of FA exposure-induced AD and brain cancer in both sex old adults with age (60–89). In addition, summer average temperature, car sales and population density were positively correlated with tropospheric FA levels in China, 2013–2019. Hence, mapping of tropospheric pollutants could be used for air quality monitoring and health risk assessment.

Classification and Prediction of Typhoon Levels by Satellite Cloud Pictures through GC-LSTM Deep Learning Model.

Typhoons are some of the most serious natural disasters, and the key to disaster prevention and mitigation is typhoon level classification. How to better use data of satellite cloud pictures to achieve accurate classification of typhoon levels has become one of classification the hot issues in current studies. A new framework of deep learning neural network, Graph Convolutional–Long Short-Term Memory Network (GC–LSTM), is proposed, which is based on the data of satellite cloud pictures of the Himawari-8 satellite in 2010–2019. The Graph Convolutional Network (GCN) is used to process the irregular spatial structure of satellite cloud pictures effectively, and the Long Short-Term Memory (LSTM) network is utilized to learn the characteristics of satellite cloud pictures over time. Moreover, to verify the effectiveness and accuracy of the model, the prediction effect and model stability are compared with other models. The results show that: the algorithm performance of this model is better than other prediction models; the prediction accuracy rate of typhoon level classification reaches 92.35%, and the prediction accuracy of typhoons and super typhoons reaches 95.12%. The model can accurately identify typhoon eye and spiral cloud belt, and the prediction results are always kept in the minimum range compared with the actual results, which proves that the GC–LSTM model has stronger stability. The model can accurately identify the levels of different typhoons according to the satellite cloud pictures. In summary, the results can provide a theoretical basis for the related research of typhoon level classification.

多元信息耦合的致灾山洪降雨预报方法

雷达预估信息(0~2 h)、数值天气预报产品(0~72 h)及基于高空和地面大气探测资料的综合预报信息(0~24 h)在不同预见期的降雨预报各有差异，预报效果上各有优劣，而针对山洪的预报存在准确率低、预警有效时间短等问题，研究面向山洪灾害防治区的数值预报模式的选取、模式最优物理参数化组合方案、同化方案、降水偏差订正技术以及基于大数据的自分型雷达估测降水最优化算法。以湖南临湘市为试验区进行验证，结果表明：WRF中尺度数值模式适用于山洪灾害降雨预报，其WSM6云微物理过程、Grell-Devenyi ensemble对流参数化方案和YSU边界层参数方案对致洪山洪暴雨过程模拟较好，基于频率(或面积)匹配的降水偏差订正方法能显著改善模式降水预报中雨量和雨区范围的系统性偏差，大数据分析方法应用于雷达估测降雨能显著提高准确度。在此研究基础上，提出了基于高空和地面大气探测、数值预报模式的0~72 h短期定量降雨预报和基于雷达的0~2 h临近定量降雨预报的多元信息耦合预报方法，将对致灾山洪的预报时间由2 h延长至72 h，并可显著提高了山洪预报的精度。 The precipitation forecasts from radar and satellite cloud pictures (with a lead time of 0 - 2 h), from upper air and ground surface atmospheric sounding (with a lead time of 0 - 24 h) and from numerical forecasting mode (with a lead time of 0 - 72 h) have different forecast effect in different forecast pe-riods. Considering the short lead time and low accuracy forecast for early warning of mountain tor-rents, study on the numerical forecasting model, the model’s optimized combination of parameters, data assimilation, correcting the errors on forecasted rainfall in flash-flood affected region and an op-timized calculating method based on big data for radar monitoring precipitation. Linxiang City of Hu-nan Province was selected as experimental area and the results show that the WRF numerical forecast is more suitable for the forecast of disasters including mountain torrents. Among them, WSM6 cloud microphysical process, Grell-Devenyi ensemble convective parameterization scheme and YSU boun-dary layer parameter configuration scheme can greatly simulate the process of mountain torrents and storm causing a flood, precipitation deviation correction method based on frequency (or area) match can considerably improve the systematic deviation in the rainfall and scope of rain area in the preci-pitation forecast, the big data analysis method used in radar rainfall forecast can remarkably improve the accuracy. A forecasting disastrous flash floods method has been proposed by coupling upper air and ground surface atmospheric sounding, the 0 - 72 h short-term quantitative precipitation forecasts (QPF) from numerical forecasting mode and the 0 - 2 h nowcast QPF based on radar, which helps to increase the lead time of flash flooding forecasts from 2 h to 72 h and enhance significantly the fore-casting accuracy.

Vectorization Method on the Color Cloud Image

The vectorization, which is an interdisciplinary combining subjects of the computer vision, computer image processing, computer graphics and artificial intelligence, is an important issue in the digital image processing. This paper makes a study of the vectorization method on the satellite color cloud image, Specific techniques such as cloud image layering, threshold selection, edge detection and tracking, feature point extraction, curve fitting are involved. This paper proposes a color layering algorithm whose parameter is the difference between luminance and saturability by analyzing the color features of the satellite cloud pictures. In this algorithm method, we first generate the reference image and then histogram equalize the reference image, afterwards do de-noises process to the above histogram and smooth it for the threshold choice. After analyzing the uncertainty of satellite cloud image edge, this paper puts forward an edge detection algorithm based on adaptive threshold. In order to modify the shortcomings of edge data of raster and edge data of chain code, this paper puts forward the corner detection method based on edge data chain. Also this paper develops a prototype system of automatic vectorization on satellite cloud images by curve fitting the feature points and gets the final vector graphics. Experiments show that the system has the basic functions of automatic extraction, recognition and vectorization for the information of satellite cloud clouds, and carry out the comprehensive verification and analysis for the theory and algorithm by using the real satellite cloud image data.

Origin of the waves in ‘A case‐study of mesoscale spectra of wind and temperature, observed and simulated’: Lee waves from the Norwegian mountains

AbstractThis note uses SAR images, satellite cloud pictures and point measurements together with simulations using the Weather Research and Forecasting (WRF) model to identify the origin of the gravity waves over Denmark on 6 November 2006, studied recently. The wave characteristics, concerning their initiation and ending, propagation, spatial orientation and wavelength, are consistent among the different data sources. This evidence and the key wave parameters derived from the WRF simulation, including the Scorer parameter and wave tilt, all suggest that the waves are lee waves generated by uplift from the Norwegian mountains. Copyright © 2011 Royal Meteorological Society

A Case Study of the Simultaneous Development of Multiple Lake-Breeze Fronts with a Boundary Layer Forecast Model

Abstract A fast-response boundary layer forecast mesoscale model has been used to simulate and to study the complex three-dimensional circulation associated with lake breezes in southwestern Ontario. The simultaneous development of lake-breeze fronts, their inland progression, and their confluence with each other were numerically simulated. The progression of a dominant lake breeze influenced and inhibited the penetration inland of other lake-breeze fronts. Modeled flow and vertical velocity distributions were in good agreement with satellite cloud pictures and meteorological data from a special mesoscale network of towers. Of particular interest were regions of strong convective activity at the confluence of lake-breeze fronts and an area of descending motion over land identified by a cloud-free area. The former is explained by the triggering mechanism of lake-breeze-induced convergence and ascending motion; the latter may be due to dynamically induced subsidence in a relatively low-lying area surrounded...

Estimation of divergent wind from OLR data for use in objective analysis over the Indian region

A scheme is formulated for the use of OLR data in the estimation of vertical velocity; divergence and then the divergent part of the wind over Indian region. In this scheme, ascending motion over cloudy region is estimated from an empirical relation between the cloud top temperature and descending motion over cloud-free region is estimated from the thermodynamic energy equation and both are blended. From this blended vertical velocity field, aivergence, velocity potential and divergent winds at all standard levels from 4 to 8 July 1979 at 00 UTC are computed. These fields are compared with satellite cloud pictures, rainfall etc and they are found to be realistic in depicting the synoptic conditions. Total wind is computed as the sum of the estimated divergent component and rotational component computed from observed wind field. For assessment of the scheme, this total wind field at 850 hPa is used as initial. guess field in univariate optimum interpolation scheme and analyses were made for the period 4 to 8 July 1979. Results show that scheme is able to produce realistic analyses which included divergent part of the wind.

Estimation of upper air relative humidity For objective analysis

A multiple regression relation was developed between upper air relative humidity
 and the related surface observations, like cloud cover, present weather and surface relative humidity etc. Using this regression relation at a number of surface observing stations the relative humidity values for upper air at 700 hPa west estimated from surface relative humidity, cloud cover and present weather for six days from 4 to 9 July 1979. In order to determine the impact of these estimated value, two sets of analyses were made using optimum interpolation scheme, one including estimated RH values and the second excluding them RMS errors were calculated for all the SIX cases, comparing with the observed radiosonde data to examine how both sets of analyses with and without estimated data fitted the observations. RMS errors were also computed comparing with ECMWF-RH Analyses. Lastly, these analyst's were compared with satellite cloud pictures and found them in close agreement with the observed data.

Use of Surface Observations to Estimate Upper Air Humidity for the Objective Analysis of Relative Humidity over Indian Region

In the present study objective analyses of relative humidity (RH) at surface and at the levels of 850, 700 and 500 hPa have been made using Gandin's (1963) optimum interpolation scheme. As the horizontal resolution of the radiosonde stations is rather inadequate for upper air humidity analysis, a scheme has been developed, following Rasmussen (1982) to estimate the upper air RH from the surface observations like surface RH, present weather and cloud cover. The relative humidities at the levels 850, 700 and 500 hPa were related to the surface observations through three separate regression relations. The RH values at 850, 700 and 500 hPa levels were estimated from the surface RH, cloud coverage and present weather using the above regression relations and subsequently the objective analyses at 00 GMT for the period from 4 July to 8 July 1979, were made using these estimated data along with the observed radiosonde data. Objective analyses were also made for the same period using only the radiosonde data for comparison to study the impact of those estimated data. Root mean square errors wore computed for all the five days by interpolating RH at the observing stations from the objectively analysed field and comparing them with the actually observed RH to examine how best the analyses (with and without estimated data) fitted the observations. Lastly they were compared with satellite cloud pictures. This study shows that the estimated upper air RH values have positive impact on the analysis of upper air RH and could be used over radiosonde data sparse region and even over oceanic regions.

Cloud characteristics of monsoon depressions as viewed by meteorological satellites

Satellite cloud pictures of west/westnorthwest moving monsoon depressions have been examined by dividing the area 10 degree latitude/longitude around the surface position of the depressions centre, into 2.5 degree grid squares. The isopleths of mean cloudiness, coefficient of variation and preferred zones of large and low cloudiness are discussed in relation to the large scale flow pattern associated with the depressions. Broad category of cloud patterns have been identified in the satellite pictures. An attempt has been made to estimate daily rainfall in different sectors of the monsoon depression from these pictures.

An estimation of the cooling process by infrared radiation in the atmosphere

Two procedure are presented for quantitative estimation of cloud cover (N), type of clouds (C), as well as base of clouds (C b) and top of clouds (C t) by using radiosonde data as well as satellite cloud pictures and radiation data. The data obtained in this way can be used as input data in the model for the estimation of the vertical profile of longwave radiative cooling.

Clouding over the Arabian Sea and the synoptic situation over India during monsoon

Satellite cloud pictures for the period 1971-75 were analysed to examine the coverage and type of the clouding over the Arabian Sea m relation to two main synoptic features of the monsoon season, namely, (I) Break m monsoon, and (2) Movement of monsoon depressions. It is found that whenever breaks appear and the monsoon trough goes to the foot of the Himalayas, Arabian Sea north of Lat. 15°N is covered with stratocumulus , cloudiness. With the revival of the monsoon, these cloud lines decrease. This situation continues when the monsoon depressions fond and move westwards till they come to Long. 80°E. When the monsoon depressions move further either to the west of Long. 80 E or to the north of Lat. 25~N the stratocumulus cloud lines increase over the Arabian Sea.

A study of the monsoon depression intensifying into cyclonic storm over land

The monsoon depression which formed over the head of the Bay of Bengal and neighbourhood on 8 September 1970 and crossed West Bengal coast near Contai on the evening of 9th, showed some unusual features. It progressively intensified into a cyclonic storm over the land although its development was rather slow. Further, it executed a loop around Kanpur. This system caused very heavy rainfall along its track, particularly over the southern parts of Uttar Pradesh. A study of this depression with the help of weather satellite cloud pictures has been presented in this paper.

Low latitude westerlies over the Indian Ocean

Summary Smoothed streamline charts, derived from satellite cloud pictures of the intertropical Indian Ocean, have been used to indicate the frequency and extent of low level westerly winds. The results suggest that surface westerlies are a much more characteristic feature of the year‐around atmospheric circulation in this region, than over other intertropical oceans. As these observations are in conflict with opinions of several earlier workers in the field, the major implications are considered in terms of the atmospheric momentum balance and the structure of circulation in the intertropical convergence zone.

An Experimental Prediction of the Tropical Atmosphere for the Case of March 1965

Abstract A two-week prediction was made, applying a general circulation model on Kurihara's global grid to an observed data set. The maps for the basic meteorological elements at 10 vertical levels for 5 days in March 1965 were analyzed manually with the aid of nephanalysis charts. This report discusses the forecast results selectively for the tropical areas only. The predicted wind, temperature, and precipitation were compared, whenever possible, with the observed data including satellite cloud pictures. The main objective was to attempt a tropical forecast for a case study, and to obtain a crude idea, based on one sample, about the feasibility of predicting tropical weather systems. Some capability in the prediction of the tropical atmosphere is evident for about 3 days, in particular for the upper troposphere, but the prediction needs considerable improvement for the lower troposphere as well as for the stratosphere.

Certain aspects of monsoon depressions as revealed Problems of by satellite pictures

The cloud distribution around typical monsoon depressions is studied with the aid of satellite cloud pictures. The depressions have asymmetric cloud distribution with the main overcast to the west and southwest of centre. The thermal structure of these depressions is studied with the help of thickness charts. They show that the well-marked depressions are associated with considerable thermal advection. The energetics of monsoon depressions has been discussed in relation to the observed thermal structure of the depressions.

A satellite automatic picture transmission (APT) ground receiving station

The paper describes a satellite automatic picture transmission (APT) ground receiving station, designed and developed at the Instruments Division, Meteorological, Office, Poona. The station has been in operation at Poona for over six months and has provided good quality Visible and infrared pictures from meteorological satellites ESSA.2, ESSA.8, Nlmbus.3 and ITOS.
 The station uses a high gain right circularly polarized helical antenna, a highly sensitive and selective FM receiver and a Mufax facsimile recorder modified suitably to record the satellite cloud pictures. The paper highlights the design details of the antenna and the FM receiver and also described the necessary modifications to the 'Mufax' facsmile recorder for recording correct satellite pictures. Future development plans are also briefly discussed.

Average forenoon cloud cover over the Arabian Sea during the southwest monsoon

From the satellite cloud pictures received at APT Unit, Bombay, the day-to-day cloud cover was determined for 2½ degree grids over the Arabian Sea during July and August for the three year period 1967-1969, Based on these data. charts showing the mean cloud cover over the Arabian Sea and the adjoining equatorial region and the percentage frequencies of occasions of 0.2 okta and 6-8 okta cloudiness for July and August are presented. Mean cloud cover over the same area during typical break monsoon and strong/normal monsoon conditions over India is also discussed.

Monsoon depression as seen in satellite pictures

Satellite cloud pictures for the periods of monsoon depressions, from formative stage to dissipative stage, during July to September, 1967-69 were examined. Five broad types of cloud patterns could be identified in these pictures and they have been empirically correlated with the observed synoptic and upper air features. The pattern of clouding readily gives an indication of the intensity of the monsoon disturbance as well as its centre. The salient features of the five cloud patterns and the associated synoptic and upper air features are briefly discussed. The principal area of heavy rains is identified from the cloud patterns.

Lee waves as evidenced by satellite cloud pictures

The paper presents the observational evidence of mountain waves in the Indian region with particular reference to the Assam and Burma hills with the help of satellite pictures. In all, sixteen cases have been studied and the observed wavelengths vary between 17-34 km. In all the cases the conditions for formation of mountain waves were found favourable as evidenced by the wind profile and thermal stability of the atmosphere.