Retrieval of water vapor using SSM/I and its relation with the onset of monsoon

Abstract. The seasonal variations and interannual variability of total precipitable water (TPW) deduced from the Special Sensor Microwave Imager (SSM/I) satellite over oceanic regions of the Indian sub-continent during the years between 1988 to 1998 show characteristic behavior. The weekly patterns of TPW are found to be closely related to the dynamics of the climatic conditions and the onset date of monsoon. The present results show that the satellite monitoring of TPW may prove as a good and reliable indicator in forecasting Indian monsoon.

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Precipitable water vapor content from ESR/SKYNET Sun-sky radiometers: validation against GNSS/GPS and AERONET over three different sites in Europe

10.5194/amt-2017-221 ◽

2017 ◽

Cited By ~ 1

Author(s):

Monica Campanelli ◽

Alessandra Mascitelli ◽

Paolo Sanò ◽

Henri Diémoz ◽

Victor Estellés ◽

...

Keyword(s):

Water Vapor ◽

Precipitable Water ◽

Climatic Conditions ◽

Precipitable Water Vapor ◽

Water Vapor Content ◽

Atmospheric Parameter ◽

High Temporal Resolution ◽

Photometric Calibration ◽

Wide Range ◽

Calibration Parameters

Abstract. The estimation of the precipitable water vapor content (W) with high temporal and spatial resolution is of great interest in both meteorological and climatological studies. Several methodologies based on remote sensing techniques have been recently developed, in order to obtain accurate and frequent measurements of this atmospheric parameter. Among them, the relative low cost and easy deployment of sun-sky radiometers, or sun-photometers, operating in several international networks, allowed the development of automatic estimations of W from these instruments with high temporal resolution. However the great problem of this methodology is the estimation of the sun-photometric calibration parameters. The objective of this paper is to validate a new methodology based on the hypothesis that the calibration parameters characterizing the atmospheric transmittance at 940 nm are dependent on vertical profiles of temperature, air pressure and moisture typical of each measurement site. To obtain the calibration parameters some simultaneously seasonal independent measurements of W taken over a large range of solar zenith angle and covering a wide range of W, are needed. In this work yearly GNSS/GPS dataset were used for obtaining a table of photometric calibration constants and the methodology was applied and validated in three European ESR-SKYNET network sites, characterized by different atmospheric and climatic conditions: Rome, Valencia and Aosta. Results were validated against the GNSS/GPS and AErosol Robotic NETwork (AERONET) W estimations. In both the validations the agreement was very high with a percentage RMSD of about 6 %, 13 % and 8 % in the case of GPS intercomparison at Rome, Aosta and Valencia, respectively, and of 8 % in the case of AERONET comparison in Valencia. Analysing the results by W classes, the present methodology was found to clearly improve W estimation at low W content when compared against AERONET in term of %Bias, bringing the agreement with the GPS (considered the reference one), from a %Bias of 5.76 to 0.52.

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Spatial Distributions and Seasonal Variations of Tropospheric Water Vapor Content over the Tibetan Plateau

Journal of Climate ◽

10.1175/jcli-d-12-00574.1 ◽

2013 ◽

Vol 26 (15) ◽

pp. 5637-5654 ◽

Cited By ~ 23

Author(s):

Yuwei Zhang ◽

Donghai Wang ◽

Panmao Zhai ◽

Guojun Gu ◽

Jinhai He

Keyword(s):

Water Vapor ◽

Tibetan Plateau ◽

Seasonal Variations ◽

Precipitable Water ◽

High Water ◽

Water Vapor Content ◽

The Tibetan Plateau ◽

Spatial Distributions ◽

Vapor Flux ◽

Horizontal Gradients

Abstract Spatial distributions and seasonal variations of tropospheric water vapor over the Tibetan Plateau and the surrounding areas are explored by means of water vapor products from the high-resolution Atmospheric Infrared Sounder (AIRS) on board the Aqua satellite and the NASA Water Vapor Project (NVAP). Because NVAP has a serious temporal inhomogeneity issue found in previous studies, the AIRS retrieval product is primarily applied here, though similar seasonal variations can be derived in both datasets. Intense horizontal gradients appear along the edges of the plateau in the lower-tropospheric (500–700 hPa) water vapor and columnar precipitable water, in particular over the regions along the southeastern boundary. Rich horizontal structures are also seen within the plateau, but with a weaker gradient. In the mid- to upper troposphere (300–500 hPa), horizontal gradients are relatively weak. It is shown that there is always a deep layer of high water vapor content over the plateau with a peak around 500 hPa, which can extend from the surface to roughly 300 hPa and even to 100 hPa at some locations. This layer of high water vapor content has consistent influence on precipitating processes in the downstream regions such as the valleys of the Yellow and Yangtze Rivers. Estimated vertically integrated water vapor flux and moisture divergence in the two layers (500–700 and 300–500 hPa) further confirm the effect of the Tibetan Plateau on the downstream regions. In particular, the mid- to upper-layer water vapor (300–500 hPa) tends to play an essential role during both the warm and cold seasons, confirmed by the spatial distribution of seasonal-mean precipitation.

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Evaluation of ERA-5 Precipitable Water Vapor Data in Plateau Areas: A Case Study of the Northern Qinghai-Tibet Plateau

Atmosphere ◽

10.3390/atmos12101367 ◽

2021 ◽

Vol 12 (10) ◽

pp. 1367

Author(s):

Jie Zhao ◽

Tiejian Li ◽

Kaifang Shi ◽

Zhen Qiao ◽

Zhongye Xia

Keyword(s):

Water Vapor ◽

Cloud Cover ◽

Coincidence Degree ◽

Precipitable Water ◽

Climatic Conditions ◽

Precipitable Water Vapor ◽

Radiosonde Data ◽

Tibet Plateau ◽

Total Cloud Cover ◽

Qinghai Tibet Plateau

In order to verify the accuracy of precipitable water vapor (PWV) in remote sensing and reanalysis datasets under different climatic conditions and ensure the reliability of analysis results, the performances of ERA-5 reanalysis PWV data and the Atmospheric Infrared Sounder (AIRS) remotely-sensed PWV data were tested in the northern Qinghai-Tibet Plateau by using weather balloon radiosonde data from meteorological stations from 2002 to 2016. The coincidence degree of total cloud cover was also verified, and then the PWV data precision with different levels of cloud cover was analyzed. The results show that: (1) Both ERA-5 and AIRS data underestimate PWV in the studied high plateau region, and higher altitude leads to greater deviation. (2) Compared with AIRS data, ERA-5 data have better consistency with radiosonde data in PWV and total cloud cover. (3) For the long-term trend of PWV, the ERA-5 data are the opposite to the radiosonde data with a clear sky, but both datasets showed a significant increasing trend in cloudy skies. It can be concluded that in high altitude areas, the ERA-5 data can be used for general analysis, but are not well qualified to reflect the changing trend of PWV under climate change.

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KORELASI MUSIMAN ANTARA ZENITH WET DELAY (ZWD) DAN DEBIT SUNGAI DI DAS CIKAPUNDUNG HULU, KAWASAN BANDUNG UTARA, JAWA BARAT

Seminar Nasional Geomatika ◽

10.24895/sng.2018.3-0.1033 ◽

2019 ◽

Vol 3 ◽

pp. 741

Author(s):

Wedyanto Kuntjoro ◽

Z.A.J. Tanuwijaya ◽

A. Pramansyah ◽

Dudy D. Wijaya

Keyword(s):

Water Vapor ◽

Precipitable Water ◽

Precipitable Water Vapor ◽

Zenith Wet Delay

Kandungan total uap air troposfer (precipitable water vapor) di suatu tempat dapat diestimasi berdasarkan karakteristik bias gelombang elektromagnetik dari satelit navigasi GPS, berupa zenith wet delay (ZWD). Pola musiman deret waktu ZWD sangat penting dalam studi siklus hidrologi khususnya yang terkait dengan kejadian-kejadian banjir. Artikel ini menganalisis korelasi musiman antara ZWD dan debit sungai Cikapundung di wilayah Bandung Utara berdasarkan estimasi rataan pola musimannya. Berdasarkan rekonstruksi sejumlah komponen harmonik ditemukan bahwa pola musiman ZWD memiliki kemiripan dan korelasi yang kuat dengan pola musiman debit sungai. Pola musiman ZWD dan debit sungai dipengaruhi secara kuat oleh fenomena pertukaran Monsun Asia dan Monsun Australia. Korelasi linier di antara keduanya menunjukkan hasil yang sangat kuat, dimana hampir 90% fluktuasi debit sungai dipengaruhi oleh kandungan uap air di troposfer dengan level signifikansi 95%. Berdasarkan spektrum amplitudo silang dan koherensi, kedua kuantitas ini nampak didominasi oleh siklus monsun satu tahunan disertai indikasi adanya pengaruh siklus tengah tahunan dan 4 bulanan.

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HGPT2: An ERA5-Based Global Model to Estimate Relative Humidity

Remote Sensing ◽

10.3390/rs13112179 ◽

2021 ◽

Vol 13 (11) ◽

pp. 2179

Author(s):

Pedro Mateus ◽

Virgílio B. Mendes ◽

Sandra M. Plecha

Keyword(s):

Water Vapor ◽

Relative Humidity ◽

Real Time ◽

Prediction Models ◽

Weather Prediction ◽

Precipitable Water ◽

Precipitable Water Vapor ◽

Global Navigation Satellite Systems ◽

International Gnss Service ◽

Weighted Mean Temperature

The neutral atmospheric delay is one of the major error sources in Space Geodesy techniques such as Global Navigation Satellite Systems (GNSS), and its modeling for high accuracy applications can be challenging. Improving the modeling of the atmospheric delays (hydrostatic and non-hydrostatic) also leads to a more accurate and precise precipitable water vapor estimation (PWV), mostly in real-time applications, where models play an important role, since numerical weather prediction models cannot be used for real-time processing or forecasting. This study developed an improved version of the Hourly Global Pressure and Temperature (HGPT) model, the HGPT2. It is based on 20 years of ERA5 reanalysis data at full spatial (0.25° × 0.25°) and temporal resolution (1-h). Apart from surface air temperature, surface pressure, zenith hydrostatic delay, and weighted mean temperature, the updated model also provides information regarding the relative humidity, zenith non-hydrostatic delay, and precipitable water vapor. The HGPT2 is based on the time-segmentation concept and uses the annual, semi-annual, and quarterly periodicities to calculate the relative humidity anywhere on the Earth’s surface. Data from 282 moisture sensors located close to GNSS stations during 1 year (2020) were used to assess the model coefficients. The HGPT2 meteorological parameters were used to process 35 GNSS sites belonging to the International GNSS Service (IGS) using the GAMIT/GLOBK software package. Results show a decreased root-mean-square error (RMSE) and bias values relative to the most used zenith delay models, with a significant impact on the height component. The HGPT2 was developed to be applied in the most diverse areas that can significantly benefit from an ERA5 full-resolution model.

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Variability and climatology of precipitable water vapor from 12-year GPS observations in Taiwan

Advances in Space Research ◽

10.1016/j.asr.2021.01.021 ◽

2021 ◽

Author(s):

Shih-Chun Pang ◽

Ta-Kang Yeh ◽

Jing-Shan Hong ◽

Chieh-Hung Chen

Keyword(s):

Water Vapor ◽

Precipitable Water ◽

Precipitable Water Vapor ◽

Gps Observations

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Water Vapor Retrievals from Spectral Direct Irradiance Measured with an EKO MS-711 Spectroradiometer—Intercomparison with Other Techniques

Remote Sensing ◽

10.3390/rs13030350 ◽

2021 ◽

Vol 13 (3) ◽

pp. 350

Author(s):

Rosa Delia García ◽

Emilio Cuevas ◽

Victoria Eugenia Cachorro ◽

Omaira E. García ◽

África Barreto ◽

...

Keyword(s):

Water Vapor ◽

Power Plants ◽

Precipitable Water ◽

Satellite System ◽

Infrared Spectrometry ◽

Radiative Balance ◽

Direct Normal Irradiance ◽

Routine Basis ◽

Solar Power Plants ◽

Global Navigation Satellite

Precipitable water vapor retrievals are of major importance for assessing and understanding atmospheric radiative balance and solar radiation resources. On that basis, this study presents the first PWV values measured with a novel EKO MS-711 grating spectroradiometer from direct normal irradiance in the spectral range between 930 and 960 nm at the Izaña Observatory (IZO, Spain) between April and December 2019. The expanded uncertainty of PWV (UPWV) was theoretically evaluated using the Monte-Carlo method, obtaining an averaged value of 0.37 ± 0.11 mm. The estimated uncertainty presents a clear dependence on PWV. For PWV ≤ 5 mm (62% of the data), the mean UPWV is 0.31 ± 0.07 mm, while for PWV > 5 mm (38% of the data) is 0.47 ± 0.08 mm. In addition, the EKO PWV retrievals were comprehensively compared against the PWV measurements from several reference techniques available at IZO, including meteorological radiosondes, Global Navigation Satellite System (GNSS), CIMEL-AERONET sun photometer and Fourier Transform Infrared spectrometry (FTIR). The EKO PWV values closely align with the above mentioned different techniques, providing a mean bias and standard deviation of −0.30 ± 0.89 mm, 0.02 ± 0.68 mm, −0.57 ± 0.68 mm, and 0.33 ± 0.59 mm, with respect to the RS92, GNSS, FTIR and CIMEL-AERONET, respectively. According to the theoretical analysis, MB decreases when comparing values for PWV > 5 mm, leading to a PWV MB between −0.45 mm (EKO vs. FTIR), and 0.11 mm (EKO vs. CIMEL-AERONET). These results confirm that the EKO MS-711 spectroradiometer is precise enough to provide reliable PWV data on a routine basis and, as a result, can complement existing ground-based PWV observations. The implementation of PWV measurements in a spectroradiometer increases the capabilities of these types of instruments to simultaneously obtain key parameters used in certain applications such as monitoring solar power plants performance.

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