A Comparison of GOES Moisture-Derived Product and GPS-IPW Data during IHOP-2002

2005 ◽  
Vol 22 (11) ◽  
pp. 1838-1845 ◽  
Author(s):  
Daniel Birkenheuer ◽  
Seth Gutman
Keyword(s):  
Water Vapor ◽  
Standard Deviation ◽  
Field Experiment ◽  
Diurnal Cycle ◽  
Precipitable Water ◽  
Data Sources ◽  
Signal Delay ◽  
Total Precipitable Water ◽  
Limited Degree ◽  
Total Column

Abstract Geostationary Operational Environmental Satellite (GOES) sounder–derived total column water vapor is compared with other data sources obtained during the 2002 International H2O Project (IHOP-2002) field experiment. Specifically, GPS-derived total integrated precipitable water (GPS-IPW) and radiosonde observations (raob) data are used to assess GOES bias and standard deviation. GPS integrated water calculated from signal delay closely matches raob data, both from special sondes launched for the IHOP-2002 exercise and routine National Weather Service (NWS) soundings. After examining the average differences between GPS and GOES product total precipitable water over the full diurnal cycle between 26 May and 15 June 2002, it was discovered that only 0000 UTC time differences were comparable to published comparisons. Differences at other times were larger and varied by a factor of 6, increasing from 0000 to 1800 UTC, and decreasing thereafter. Reasons for this behavior are explored to a limited degree but with no clear answers to explain the observations. It is concluded that a component of the GOES total precipitable water error (between sonde launches) might be missed when solely assessing the data against synoptic raobs.

scholarly journals On the Diurnal Cycle of GPS-Derived Precipitable Water Vapor over Sumatra

2019 ◽  
Vol 76 (11) ◽  
pp. 3529-3552
Author(s):  
Giuseppe Torri ◽  
David K. Adams ◽  
Huiqun Wang ◽  
Zhiming Kuang
Keyword(s):  
Water Vapor ◽  
Diurnal Cycle ◽  
Wrf Model ◽  
Precipitable Water ◽  
Active Phase ◽  
Precipitable Water Vapor ◽  
Tectonic Activity ◽  
Western Coast ◽  
The Impact ◽  
Spectrometer Data

Abstract Convective processes in the atmosphere over the Maritime Continent and their diurnal cycles have important repercussions for the circulations in the tropics and beyond. In this work, we present a new dataset of precipitable water vapor (PWV) obtained from the Sumatran GPS Array (SuGAr), a dense network of GPS stations principally for examining seismic and tectonic activity along the western coast of Sumatra and several offshore islands. The data provide an opportunity to examine the characteristics of convection over the area in greater detail than before. In particular, our results show that the diurnal cycle of PWV on Sumatra has a single late afternoon peak, while that offshore has both a midday and a nocturnal peak. The SuGAr data are in good agreement with GPS radio occultation data from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) mission, as well as with imaging spectrometer data from the Ozone Measuring Instrument (OMI). A comparison between SuGAr and the NASA Water Vapor Project (NVAP), however, shows significant differences, most likely due to discrepancies in the temporal and spatial resolutions. To further understand the diurnal cycle contained in the SuGAr data, we explore the impact of the Madden–Julian oscillation (MJO) on the diurnal cycle with the aid of the Weather Research and Forecasting (WRF) Model. Results show that the daily mean and the amplitude of the diurnal cycle appear smaller during the suppressed phase relative to the developing/active MJO phase. Furthermore, the evening/nighttime peaks of PWV offshore appear later during the suppressed phase of the MJO compared to the active phase.

scholarly journals Verification of NWP Model Analyses and Radiosonde Humidity Data with GPS Precipitable Water Vapor Estimates during AMMA

2009 ◽  
Vol 24 (4) ◽  
pp. 1085-1101 ◽  
Author(s):  
O. Bock ◽  
M. Nuret
Keyword(s):  
Water Vapor ◽  
Diurnal Cycle ◽  
Bias Correction ◽  
Precipitable Water ◽  
Precipitable Water Vapor ◽  
Precipitation Forecast ◽  
Weather Forecasts ◽  
Multidisciplinary Analysis ◽  
Correction Scheme ◽  
Nwp Model

Abstract This paper assesses the performance of the European Centre for Medium-Range Weather Forecasts-Integrated Forecast System (ECMWF-IFS) operational analysis and NCEP–NCAR reanalyses I and II over West Africa, using precipitable water vapor (PWV) retrievals from a network of ground-based GPS receivers operated during the African Monsoon Multidisciplinary Analysis (AMMA). The model analyses show reasonable agreement with GPS PWV from 5-daily to monthly means. Errors increase at shorter time scales, indicating that these global NWP models have difficulty in handling the diurnal cycle and moist processes at the synoptic scale. The ECMWF-IFS analysis shows better agreement with GPS PWV than do the NCEP–NCAR reanalyses (the RMS error is smaller by a factor of 2). The model changes in ECMWF-IFS were not clearly reflected in the PWV error over the period of study (2005–08). Radiosonde humidity biases are diagnosed compared to GPS PWV. The impacts of these biases are evidenced in all three model analyses at the level of the diurnal cycle. The results point to a dry bias in the ECMWF analysis in 2006 when Vaisala RS80-A soundings were assimilated, and a diurnally varying bias when Vaisala RS92 or Modem M2K2 soundings were assimilated: dry during day and wet during night. The overall bias is offset to wetter values in NCEP–NCAR reanalysis II, but the diurnal variation of the bias is observed too. Radiosonde bias correction is necessary to reduce NWP model analysis humidity biases and improve precipitation forecast skill. The study points to a wet bias in the Vaisala RS92 data at nighttime and suggests that caution be used when establishing a bias correction scheme.

scholarly journals On the Climatology of Precipitable Water and Water Vapor Flux in the Mid-Atlantic Region of the United States

2015 ◽  
Vol 16 (1) ◽  
pp. 70-87 ◽  
Author(s):  
Young-Hee Ryu ◽  
James A. Smith ◽  
Elie Bou-Zeid
Keyword(s):  
United States ◽  
Water Vapor ◽  
Diurnal Cycle ◽  
Precipitable Water ◽  
The United States ◽  
Radiosonde Data ◽  
Atlantic Region ◽  
Water Vapor Flux ◽  
Vapor Flux ◽  
Diurnal Cycles

Abstract The seasonal and diurnal climatologies of precipitable water and water vapor flux in the mid-Atlantic region of the United States are examined. A new method of computing water vapor flux at high temporal resolution in an atmospheric column using global positioning system (GPS) precipitable water, radiosonde data, and velocity–azimuth display (VAD) wind profiles is presented. It is shown that water vapor flux exhibits striking seasonal and diurnal cycles and that the diurnal cycles exhibit rapid transitions over the course of the year. A particularly large change in the diurnal cycle of meridional water vapor flux between spring and summer seasons is found. These features of the water cycle cannot be resolved by twice-a-day radiosonde observations. It is also shown that precipitable water exhibits a pronounced seasonal cycle and a less pronounced diurnal cycle. There are large contrasts in the climatology of water vapor flux between precipitation and nonprecipitation conditions in the mid-Atlantic region. It is hypothesized that the seasonal transition of large-scale flow environments and the change in the degree of differential heating in the mountainous and coastal areas are responsible for the contrasting diurnal cycle between spring and summer seasons.

scholarly journals ANALISIS TEMPERATUR DAN UAP AIR BERBASIS SATELIT TERRA/AQUA (MODIS, LEVEL-2)

2016 ◽  
Vol 13 (1) ◽  
Author(s):  
Sinta Berliana Sipayung ◽  
. Krismianto ◽  
. Risyanto
Keyword(s):  
Water Vapor ◽  
Data Extraction ◽  
Precipitable Water ◽  
Hierarchical Data ◽  
Grid Data ◽  
Data Format ◽  
Total Precipitable Water ◽  
Atmospheric Profiles ◽  
Hierarchical Data Format ◽  
Level 2

Terra and Aqua satellites that consist of multiple sensors including MODIS instruments, which is operated to detect the phenomena that exist on land, sea and atmosphere. Not a lot of data extracted especially for Indonesia region the associated with atmospheric data, because the product is still in the raw data (level-0). For data extraction of level-0 to level-2 needed software IMAPP (International MODIS/airs Processing Package) so displays some data atmospheric parameters including MOD 04 - Aerosol, MOD 05 - Total precipitable Water (Water Vapor), MOD 06 - Cloud, MOD 07 - Atmospheric Profiles, MOD 08 - gridded Atmospheric and MOD 35 in HDF4 format (Hierarchical Data Format-4) swath. This paper discussed only MOD07/MYD07 atmospheric profiles level-2 related parameters such as the temperature of the atmosphere at an altitude of 780 hPa and water vapor at a height of 700 hPa. This study aimed to analyze the phenomena in the atmosphere, based on extraction method Atmospheric Profiles in the resolution 1km,  that consists of temperature and moisture level-2, in the format hdf4 daily swath into data daily and monthly grid in .dat format, in the period of December 2014, January, July, and August 2015, especially in the area of Indonesia. The comparison between the results of the extraction swath and grid data from Terra/Aqua MODIS, that parameter atmospheric for the temperature has R-sqare an average of 0.72 and water vapor 0.74, while the RMSE temperature and water vapor are 0.88 and 0.29. Abstrak Satelit Terra dan Aqua yang terdiri dari beberapa sensor diantaranya instrumen MODIS, yang dioperasikan untuk mendeteksi fenomena yang ada di darat, laut, dan atmosfer. Belum banyak data yang diekstrak khususnya untuk wilayah Indonesia yang terkait dengan data atmosfer, karena produk MODIS masih berupa data mentah (level-0). Untuk ekstraksi data dari level-0 menjadi level-2 dibutuhkan software International MODIS/AIRS Processing Package (IMAPP) sehingga menampilkan beberapa data parameter atmosfer diantaranya MOD 04 - Aerosol, MOD 05 - Total Precipitable Water (Water Vapor), MOD 06 - Cloud, MOD 07 - Atmospheric Profiles, MOD 08 - Gridded Atmospheric dan MOD 35 swath dalam format Hierarchical Data Format-4 (HDF4). Pada makalah ini yang dibahas hanya MOD07/MYD07 atmospheric profiles level-2 yang berkaitan dengan parameter atmosfer seperti temperatur pada ketinggian 780 hPa dan uap air pada ketinggian 700 hPa. Penelitian ini bertujuan untuk menganalisis hasil ekstraksi data Atmospheric Profiles dari format HDF4 swath harian menjadi data grided harian, bulanan dalam format .dat serta aplikasinya pada periode bulan Desember 2014, Januari, Juli, dan Agustus 2015, khususnya wilayah Indonesia dalam resolusi 1km yang terdiri dari temperatur dan uap air level-2. Perbandingan antara hasil ekstraksi data MODIS swath dan data MODIS grided Terra/Aqua untuk parameter temperatur atmosfer mempunyai R-sqare rata-rata 0.72 dan uap air 0.74, sedangkan RMSE untuk temperatur dan uap air sebesar 0.88 dan 0.29.

scholarly journals Diurnal Cycle of Convective Instability around the Central Mountains in Japan during the Warm Season

2005 ◽  
Vol 62 (5) ◽  
pp. 1626-1636 ◽  
Author(s):  
Tomonori Sato ◽  
Fujio Kimura
Keyword(s):  
Water Vapor ◽  
Diurnal Cycle ◽  
Convective Instability ◽  
Potential Temperature ◽  
Warm Season ◽  
Precipitable Water ◽  
Specific Humidity ◽  
High Temporal Resolution ◽  
Mountainous Areas ◽  
Diurnal Cycles

Abstract Convective rainfall often shows a clear diurnal cycle. The nighttime peak of convective activity prevails in various regions near the world's mountains. The influence of the water vapor and convective instability upon nocturnal precipitation is investigated using a numerical model and observed data. Recent developments in GPS meteorology allow the estimation of precipitable water vapor (PWV) with a high temporal resolution. A dense network has been established in Japan. The GPS analysis in August 2000 provides the following results: In the early evening, a high-GPS-PWV region forms over mountainous areas because of the convergence of low-level moisture, which gradually propagates toward the adjacent plain before midnight. A region of convection propagates simultaneously eastward into the plain. The precipitating frequency correlates fairly well with the GPS-PWV and attains a maximum value at night over the plain. The model also provides similar characteristics in the diurnal cycles of rainfall and high PWV. Abundant moisture accumulates over the mountainous areas in the afternoon and then advects continuously toward the plain by the ambient wind. The specific humidity greatly increases at about the 800-hPa level over the plain at night, and the PWV reaches its nocturnal maximum. The increase in the specific humidity causes an increase of equivalent potential temperature at about the 800-hPa level; as a result, the convective instability index becomes more unstable over the plain at night. These findings are consistent with the diurnal cycle of the observed precipitating frequency.

scholarly journals An Integrated Assessment of Measured and Modeled Integrated Water Vapor in Switzerland for the Period 2001–03

2005 ◽  
Vol 44 (7) ◽  
pp. 1033-1044 ◽  
Author(s):  
G. Guerova ◽  
E. Brockmann ◽  
F. Schubiger ◽  
J. Morland ◽  
C. Mätzler
Keyword(s):  
Water Vapor ◽  
Standard Deviation ◽  
Diurnal Cycle ◽  
Integrated Assessment ◽  
Mesoscale Model ◽  
Microwave Radiometer ◽  
Measurement Techniques ◽  
Bimodal Distribution ◽  
Limited Area ◽  
Dry Bias

Abstract In this paper an integrated assessment of the vertically integrated water vapor (IWV) measured by radiosonde, microwave radiometer (MWR), and GPS and modeled by the limited-area mesoscale model of MeteoSwiss is presented. The different IWV measurement techniques are evaluated through intercomparisons of GPS to radiosonde in Payerne, Switzerland, and to the MWR operated at the Institute of Applied Physics at the University of Bern in Switzerland. The validation of the IWV field of the nonhydrostatic mesoscale Alpine Model (aLMo) of MeteoSwiss is performed against 14 GPS sites from the Automated GPS Network of Switzerland (AGNES) in the period of 2001–03. The model forecast and the nudging analysis are evaluated, with special attention paid to the diurnal cycle. The results from the GPS–radiosonde intercomparison are in agreement, but with a bimodal distribution of the day-to-night basis. At 0000 UTC, the bias is negative (−0.4 kg m−2); at 1200 UTC, it is positive (0.9 kg m−2) and the variability increases. The intercomparison of GPS to MWR shows better agreement (0.4 kg m−2), with a small increase of the daytime bias with 0.3 kg m−2. The intercomparison of MWR to the radiosonde gives a bimodal distribution of the bias, with an increase in the standard deviation at the daytime measurement. The relative bias is negative (−3%) at 0000 UTC and is positive (3%) at 1200 UTC. Based on this cross correlation, it can be concluded that the bimodal distribution is a result of radiosonde humidity measurements. Possible reasons are the solar-heating correction or sensor errors. The monthly bias and standard deviation of aLMo exhibit a strong seasonal dependence with a pronounced dry bias during the warm months of May–October 2002. The diurnal IWV cycle in 2001 shows good model performance between 0000 and 0900 UTC but IWV underestimation by up to 1.5 kg m−2 for the rest of the day. In 2002 the diurnal cycle shows a systematic dry bias in both the analysis and forecast that is more pronounced in the analysis. This substantial underestimation of IWV was found to correlate with overestimation of aLMo precipitation, especially light precipitation up to 0.1 mm (6 h)−1 in 2002. There is strong evidence that this underestimation can be related to the dry radiosonde bias in midday summer observations. The aLMo dry bias is about 1.0–1.5 kg m−2 greater in the nudging analysis as compared with the forecast initialized at 0000 UTC.

Sign in / Sign up

Export Citation Format

Share Document