Evaluation of daily and diurnal signals of total precipitable water (TPW) over the Indian Ocean based on TMI retrieved 3-day composite estimates and radiosonde data

2007 ◽  
Vol 27 (6) ◽  
pp. 761-770 ◽  
Author(s):  
V. Sajith ◽  
Jimmy O. Adegoke ◽  
Santosh K. Raghavan ◽  
H. S. Ram Mohan ◽  
Vinod Kumar ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Precipitable Water ◽  
Radiosonde Data ◽  
Total Precipitable Water ◽  
The Indian Ocean

scholarly journals Evaluation of MODIS Water Vapour Products over ALGERIA using Radiosonde Data

2021 ◽  
Vol 44 ◽  
Author(s):  
Houaria Namaoui ◽  
Salem Kahlouche ◽  
Ahmed Hafidh Belbachir
Keyword(s):  
Water Vapour ◽  
Satellite Data ◽  
Correlation Coefficients ◽  
Precipitable Water ◽  
Radiosonde Data ◽  
Precipitable Water Vapour ◽  
Total Precipitable Water ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer

Remote sensing of atmospheric water vapour using GNSS and Satellite data has become an efficient tool in meteorology and climate research. Many satellite data have been increasingly used to measure the content of water vapour in the atmosphere and to characterize its temporal and spatial variations. In this paper, we have used observations from radiosonde data collected from three stations (Algiers, Bechar and Tamanrasset) in Algeria from January to December 2012 to evaluate Moderate Resolution Imaging Spectroradiometer (MODIS) total precipitable water vapour (PWV) products. Results show strong agreement between the total precipitable water contents estimated based on radiosondes observations and the ones measured by the sensor MODIS with the correlation coefficients in the range 0.69 to 0.95 and a mean bias, which does not exceed 1.5.  

scholarly journals Comparison Analysis of Total Precipitable Water of Satellite-Borne Microwave Radiometer Retrievals and Island Radiosondes

Atmosphere ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 390
Author(s):  
Ji-Ping Guan ◽  
Yan-Tong Yin ◽  
Li-Feng Zhang ◽  
Jing-Nan Wang ◽  
Ming-Yang Zhang
Keyword(s):  
Microwave Radiometer ◽  
Correlation Coefficients ◽  
Precipitable Water ◽  
Radiosonde Data ◽  
Mean Values ◽  
Total Precipitable Water ◽  
Comparison Results ◽  
Almost All ◽  
Mean Square Errors ◽  
Dry Bias

Total precipitable water (TPW) of satellite-borne microwave radiometer retrievals is compared with the data that were collected from 49 island radiosonde stations for the period 2007–2015. Great consistency was found between TPW measurements made by radiosonde and eight satellite-borne microwave radiometers, including SSMI-F13, SSMI-F14, SSMIS-F16, SSMIS-F17, AMSR-E, AMSR-2, GMI, and WindSat. Mean values of the TPW differences for eight satellites ranged from −0.51 to 0.38mm, both root mean square errors and standard deviations were around 3mm, and all of the correlation coefficients between satellite TPW retrievals and radiosonde TPW for each satellite can reach 0.99. Subsequently, an analysis of the comparison results was conducted, which revealed three problems in the satellite TPW retrieval and two problems in radiosonde data. For TPW retrievals of satellite, when the values are above 60 mm, the precision of TPW retrieval significantly decreases with a distinct dry bias, which can reach 4 mm; additionally, abias related to wind speed and the uncertainty with the TPW retrieval in the presence of rain, which is stronger than 1mm/h, was found. The TPW measurements of radiosonde made by the type of IM-MK3 from India were quite unreliable, and almost all of the radiosonde data during the daytime were plagued by a dry bias.

Hemispheric Insolation Forcing of the Indian Ocean and Asian Monsoon: Local versus Remote Impacts*

2006 ◽  
Vol 19 (23) ◽  
pp. 6195-6208 ◽  
Author(s):  
Xiaodong Liu ◽  
Zhengyu Liu ◽  
John E. Kutzbach ◽  
Steven C. Clemens ◽  
Warren L. Prell
Keyword(s):  
Indian Ocean ◽  
South Asian ◽  
Summer Monsoon ◽  
Asian Monsoon ◽  
Tropical Indian Ocean ◽  
Precipitable Water ◽  
The South ◽  
Summer Insolation ◽  
The Indian Ocean ◽  
Insolation Forcing

Abstract Insolation forcing related to the earth’s orbital parameters is known to play an important role in regulating variations of the South Asian monsoon on geological time scales. The influence of insolation forcing on the Indian Ocean and Asian monsoon is studied in this paper by isolating the Northern and Southern Hemispheric insolation changes in several numerical experiments with a coupled ocean–atmosphere model. The focus is on the response of South Asian summer rainfall (monsoon strength) with emphasis on impacts of the local versus remote forcing and possible mechanisms. The model results show that both Northern Hemisphere (NH) and Southern Hemisphere (SH) summer insolation changes affect the Indian Ocean and Asian monsoon as a local forcing (in the same hemisphere), but only the SH changes result in remote (in the other hemisphere) forcing. The NH insolation change has a local and immediate impact on NH summer monsoons from North Africa to South and East Asia, while the SH insolation change has a remote and seasonal-scale delayed effect on the South Asian summer monsoon rainfall. When the SH insolation is increased from December to April, the sea surface temperature (SST) in the southern tropical Indian Ocean remains high from January to July. The increased SST produces more atmospheric precipitable water over the southern tropical Indian Ocean by promoting evaporation from the ocean. The enhanced precipitable water over the southern Indian Ocean is transported northward to the South Asian monsoon region by the lower-tropospheric mean cross-equatorial flows with the onset of the Asian monsoon increasing precipitable water over South Asia, eventually leading to the increase of Indian summer monsoon precipitation. Thus, these model experiments, while idealized and not fully representing actual orbitally forced insolation changes, confirm the broadscale response of northern monsoons to NH summer insolation increases and also illustrate how SH summer insolation increases can have a delayed influence on the Indian summer monsoon.

scholarly journals Vertical Moist Thermodynamic Structure and Spatial–Temporal Evolution of the MJO in AIRS Observations

2006 ◽  
Vol 63 (10) ◽  
pp. 2462-2485 ◽  
Author(s):  
Baijun Tian ◽  
Duane E. Waliser ◽  
Eric J. Fetzer ◽  
Bjorn H. Lambrigtsen ◽  
Yuk L. Yung ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Temporal Evolution ◽  
Lower Troposphere ◽  
Western Pacific ◽  
Radiosonde Data ◽  
Temperature Structure ◽  
Free Troposphere ◽  
Thermodynamic Structure ◽  
Low Level ◽  
The Indian Ocean

Abstract The atmospheric moisture and temperature profiles from the Atmospheric Infrared Sounder (AIRS)/Advanced Microwave Sounding Unit on the NASA Aqua mission, in combination with the precipitation from the Tropical Rainfall Measuring Mission (TRMM), are employed to study the vertical moist thermodynamic structure and spatial–temporal evolution of the Madden–Julian oscillation (MJO). The AIRS data indicate that, in the Indian Ocean and western Pacific, the temperature anomaly exhibits a trimodal vertical structure: a warm (cold) anomaly in the free troposphere (800–250 hPa) and a cold (warm) anomaly near the tropopause (above 250 hPa) and in the lower troposphere (below 800 hPa) associated with enhanced (suppressed) convection. The AIRS moisture anomaly also shows markedly different vertical structures as a function of longitude and the strength of convection anomaly. Most significantly, the AIRS data demonstrate that, over the Indian Ocean and western Pacific, the enhanced (suppressed) convection is generally preceded in both time and space by a low-level warm and moist (cold and dry) anomaly and followed by a low-level cold and dry (warm and moist) anomaly. The MJO vertical moist thermodynamic structure from the AIRS data is in general agreement, particularly in the free troposphere, with previous studies based on global reanalysis and limited radiosonde data. However, major differences in the lower-troposphere moisture and temperature structure between the AIRS observations and the NCEP reanalysis are found over the Indian and Pacific Oceans, where there are very few conventional data to constrain the reanalysis. Specifically, the anomalous lower-troposphere temperature structure is much less well defined in NCEP than in AIRS for the western Pacific, and even has the opposite sign anomalies compared to AIRS relative to the wet/dry phase of the MJO in the Indian Ocean. Moreover, there are well-defined eastward-tilting variations of moisture with height in AIRS over the central and eastern Pacific that are less well defined, and in some cases absent, in NCEP. In addition, the correlation between MJO-related midtropospheric water vapor anomalies and TRMM precipitation anomalies is considerably more robust in AIRS than in NCEP, especially over the Indian Ocean. Overall, the AIRS results are quite consistent with those predicted by the frictional Kelvin–Rossby wave/conditional instability of the second kind (CISK) theory for the MJO.

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