Effect Of Atmospheric Water Vapor Research Articles

Acceleration Effect of Atmospheric Water Vapor on the Thermal Decomposition of Calcium Carbonate: A Comparison of Various Resources and Kinetic Parameterizations

Acceleration Effect of Atmospheric Water Vapor on the Thermal Decomposition of Calcium Carbonate: A Comparison of Various Resources and Kinetic Parameterizations

Individual effects of atmospheric water vapor and carbon dioxide on the kinetics of the thermal decomposition of granular malachite.

This study examined the effects of atmospheric water vapor and CO2 on the thermal decomposition of granular malachite as a model process for the thermal decomposition of large and compact agglomerate solids. In previous studies in a dry N2 gas stream, the thermal decomposition of the granular malachite exhibited physico-geometrically constrained two-step mass loss behaviors accompanied by the swelling of granular particles and crack formation in the surface product layer of each granule. In the presence of atmospheric water vapor, the reaction was shifted systematically to lower temperatures with increasing atmospheric water vapor pressure (p(H2O)) by maintaining the two-step mass loss behavior. Kinetic analyses of the two-step heterogeneous process and subsequent universal kinetic description for each reaction step over different p(H2O) values demonstrated that the catalytic effect of atmospheric water vapor is more significant in the first reaction step because of the surface reaction. Conversely, in the presence of atmospheric CO2, the reaction shifted systematically to higher temperatures with increasing partial pressure of CO2 where the surface and internal reaction steps were more clearly separated, and additional mass-loss steps appeared to complete the reaction. The enhanced retardation effects of atmospheric CO2 as the mass-loss process advanced were confirmed by kinetic analyses of the empirically deconvoluted five-step reaction process. This phenomenon was explained by the effects of atmospheric CO2 on the construction of the surface product layer that helps block the diffusional removal of the gaseous product and increases the internal gaseous pressure.

Effect of atmospheric water vapor on independent-parallel thermal dehydration of a compacted composite of an inorganic hydrate: sodium carbonate monohydrate grains comprising crystalline particles and a matrix.

The effect of atmospheric water vapor on the thermal dehydration of sodium carbonate monohydrate (SC-MH), which was characterized as cubic grains of a compacted composite comprising columnar SC-MH crystals and a matrix, was systematically assessed using a humidity-controlled thermogravimetry system at various atmospheric water vapor pressures (p(H2O)). The thermal dehydration of the SC-MH compacted composite occurred via an induction period (IP) and partially overlapping two-step mass loss steps due to the thermal dehydration of the SC-MH matrix and columnar crystals. All component reaction steps were retarded with an increase in the p(H2O) value. The kinetics of individual reaction steps were universally described over different temperatures and p(H2O) values based on a kinetic equation that considered p(H2O) and the equilibrium pressure of the thermal dehydration. Additionally, the physico-geometrical consecutive surface reaction (SR) and subsequent phase boundary-controlled reaction (PBR) model was employed to describe the first mass loss step. The difference between the effects of atmospheric p(H2O) on SR and PBR processes was parameterized via an advanced kinetic analysis. The kinetic behavior of the second mass loss step was discussed based on a three-dimensional contracting geometry model with accelerating reaction interface advancement, where the changes in the rate behavior with atmospheric p(H2O) were explained by the total effect of atmospheric and self-generated p(H2O) on the kinetics. The present results provide additional insights into the independent-parallel thermal decomposition kinetics of composite materials by considering the effects of atmospheric and self-generated gases.

Kinetics of component reactions in calcium looping appeared during the multistep thermal decomposition of Portland cement under various atmospheric conditions

Calcium looping (CaL) reactions in a Ca(OH)2-CaCO3-CaO system for energy storage and CO2 absorption occur during the thermal decomposition of cement and concrete materials. Herein, we report the kinetic behavior of the reactions in a cement matrix as the necessary information for establishing a CaL cycle supported by cement/concrete materials. The thermal decomposition of Portland cement samples, characterized by different Ca(OH)2/CaCO3 ratios, under different atmospheric water vapor and CO2 conditions were investigated to reveal the kinetic behavior of the component reactions and the changes with atmospheric conditions. The multistep thermal decomposition, characteristic of each sample and atmospheric condition, were separated into individual reaction steps through a kinetic deconvolution analysis. Using the extracted kinetic curves for the reactions of Ca(OH)2 and CaCO3, retardation effects of atmospheric water vapor and CO2 on the thermal decompositions of Ca(OH)2 and CaCO3, respectively, were kinetically described by introducing different accommodation functions (AF) comprised of the partial pressures of the gases and their equilibrium pressure. In addition, the kinetic description of the catalytic effect of water vapor on the thermal decomposition of CaCO3 was achieved by introducing alternative AF of water vapor pressure. The thermally induced carbonation of Ca(OH)2, which occurred in the presence of atmospheric CO2, was characterized kinetically as physico-geometrically regulated consecutive reactions of thermal decomposition of Ca(OH)2 and subsequent carbonation of the as-produced CaO. Kinetic information concerning the reactions of Ca(OH)2 and CaCO3 in the cement materials is reported in details.

Mapping of thermal power plant emitted atmospheric carbon dioxide concentration using AVIRIS-NG data and atmospheric radiative transfer model simulations

Our study demonstrates the potential of Airborne Visible/Infrared Imaging Spectrometer Next Generation (AVIRIS-NG) hyperspectral data and radiative transfer modeling to retrieve the atmospheric carbon dioxide (CO2) concentration from point source emission of one of India’s major coal-fed super thermal power plants at Kota, Rajasthan, India. AVIRIS-NG data with synchronous in situ measurements were collected as a part of the first ISRO-NASA joint airborne hyperspectral science campaign in India. The method utilized in our study includes theoretical simulations of at-sensor radiance in AVIRIS-NG spectral bands through the atmospheric radiative transfer model MODTRAN. Simulations were performed for the specific scene-sensor-atmospheric conditions pertaining to AVIRIS-NG overpass over Kota site. To eliminate the interfering effect of atmospheric water vapor with CO2 concentrations, simulations pertaining to variable water vapor values varying from 0.25 to 4.5 g / cm2 were also carried out, which in turn were utilized to normalize the water vapor effects. Based upon the simulation results pertaining to the specific absorption bands of CO2 in the shortwave infrared spectral range of AVIRIS-NG radiance data, a theoretical model was established between continuum interpolated band ratio (CIBR) and CO2 concentration. The CIBR − CO2 model coefficients for each of the water vapor subranges were then applied to AVIRIS-NG L1 radiance data to obtain the CO2 concentration map of the study area. A distinct CO2 plume could be detected from the coal-fed Kota Super Thermal Power Station with the CO2 concentration (XCO2) of the order of more than 500 ppmv near the power plant stacks. A range of XCO2 from 400 to 550 ppmv was observed within the scene. Our study has provided promising results in mapping the atmospheric CO2 content from the point source using the high-resolution airborne hyperspectral AVIRIS-NG data.

Influences of atmospheric water vapor on spectral effective emissivity of a single-layer radiative cooling coating

Radiative cooling technology can emit infrared heat to the outer space through the "sky window" for cooling without consuming energy, which had drawn more and more attention. However, some researches reported that there was a significantly different cooling performance at different atmospheric total water vapor columns (TWC) conditions. In this study, taking a simple single-layer radiative cooling coating containing two kinds of particle mixture (SiO₂, TiO₂) as example, the spectral effective emissivity of the radiative cooling coating was proposed to evaluate the effect of the atmospheric water vapor on the cooling performance. The spectral effective emissivity of the coating was obtained through multiplying spectral emissivity of the coating by the atmospheric transmittivity, where the spectral emissivity was calculated by combining an algorithm for calculating radiative properties of the multi-particle system with the Monte Carlo ray-tracing method (MCRT). The effects of different atmospheric water vapor on the spectral effective emissivity of the simple single-layer radiative cooling coating containing different particles size, volume fraction and thickness were studied to improve the cooling performance of the coating. The results showed that with increasing TWC from 0 to 7000 atm-cm, the average effective emissivity of the simple single-layer coating decreased from 79.5% to 35.3%, with a decrease of 44.2%. The research results are of great significance to the further application development and the design criterion of radiative cooling materials in different atmospheric water vapor environments.

A split-window method to retrieving sea surface temperature from landsat 8 thermal infrared remote sensing data in offshore waters

Sea surface temperature (SST) is an important parameter used to describe the air-sea interaction and the state of marine structures. Atmospheric water vapor has a significant attenuation effect on thermal infrared information, which will reduce the accuracy of SST inversion. However, the effect of atmospheric water vapor on the inversion accuracy is not considered carefully in the existing SST inversion algorithm. In this study, a new method is proposed for retrieving SST from Landsat 8 Thermal Infrared Remote Sensing (TIRS) data based on the variation of atmospheric water vapor content (wvc). First, simulating atmospheric conditions by using moderate resolution atmospheric transmission (MODTRAN) based on atmospheric profiles data (air temperature and pressure). Second, calculating the bright temperature based on the radiation transfer equation and Planck's law. Then, constructing the SST retrieval model of thermal infrared remote sensing based on wvc. Finally, evaluating the accuracy of the proposed model by using simulation data. The root mean square errors (RMSEs) are within 0.5 K, indicating that the accuracy of the model is good in theory. In addition, taking the Zhoushan sea area as the research area, SST is retrieved by Landsat 8 TIRS data. The accuracy of inversion results is evaluated by advanced very high-resolution radiometer (AVHRR) SST products. The bias and RMSE based on the AVHRR SST products are within 1 K and 2 K, respectively. The results show that the accurate SST with high spatial resolution was successfully obtained by using the method. The study is of great significance to the acquisition of marine structural parameters, the exploitation of marine resources, and the monitoring of marine disasters.

Effect of atmospheric water vapor on radiative cooling performance of different surfaces

The sub-ambient clear sky daytime radiative cooling has been achieved recently by applying advanced nanofabrication technologies, which attracted significant research attention in this area. However, there are also several researches which reported that radiative coolers with excellent thermal radiative spectrum failed to achieve sub-ambient radiative cooling. To elucidate the difference, in this work, we perform a detailed investigation of ambient conditions, in particular, water vapor density, on the performance of radiative coolers. We first present the details of how to estimate the performance of radiative coolers under different water vapor concentration and simulate the transmittance and emitted radiation of atmosphere as well as the cooling performance of the ideal selective emitter, which finds the cooling power decreases by 86.6 W/m2 with increasing total water vapor column. Furthermore, the cooling performance of an integrated photonic solar reflector and thermal emitter with atmospheric profiles in California and Hong Kong were calculated and compared with experiment result. To verify our calculation, nighttime on-site cooling performance of a reference film (Al foil) and two selective emitters (DESR-M and double-layer coating) was measured in several ambient conditions. Our research reveals how the ambient humidity affects the radiative cooling performance by both theoretical and experimental analysis and is important for the further application development of radiative coolers.

MITIGATION ATMOSPHERIC EFFECTS IN INTERFEROGRAM WITH USING INTEGRATED MERIS/MODIS DATA AND A CASE STUDY OVER SOUTHERN CALIFORNIA

Abstract. Interferometric synthetic aperture radar(InSAR), as a space geodetictechnology, had been testified a high potential means of earth observation providing a method fordigital elevation model (DEM) and surface deformation monitoring of high precision. However, the accuracy of the interferometric synthetic aperture radar is mainly limited by the effects of atmospheric water vapor. In order to effectively measure topography or surface deformations by synthetic aperture radar interferometry (InSAR), it is necessary to mitigate the effects of atmospheric water vapor on the interferometric signals. This paper analyzed the atmospheric effects on the interferogram quantitatively, and described a result of estimating Precipitable Water Vapor (PWV) from the the Medium Resolution Imaging Spectrometer (MERIS), Moderate Resolution Imaging Spectroradiometer (MODIS) and the ground-based GPS, compared the MERIS/MODIS PWV with the GPS PWV. Finally, a case study for mitigating atmospheric effects in interferogramusing with using the integration of MERIS and MODIS PWV overSouthern California is given. The result showed that such integration approach benefits removing or reducing the atmospheric phase contribution from the corresponding interferogram, the integrated Zenith Path Delay Difference Maps (ZPDDM) of MERIS and MODIS helps reduce the water vapor effects efficiently, the standard deviation (STD) of interferogram is improved by 23 % after the water vapor correction than the original interferogram.

InSAR Water Vapor Data Assimilation into Mesoscale Model MM5: Technique and Pilot Study

In this study, a technique developed to retrieve integrated water vapor from interferometric synthetic aperture radar (InSAR) data is described, and a three-dimensional variational assimilation experiment of the retrieved precipitable water vapor into the mesoscale weather prediction model MM5 is carried out. The InSAR measurements were available in the framework of the European Space Agency (ESA) project for the “Mitigation of electromagnetic transmission errors induced by atmospheric water vapor effects” (METAWAVE), whose goal was to analyze and possibly predict the phase delay induced by atmospheric water vapor on the spaceborne radar signal. The impact of the assimilation on the model forecast is investigated in terms of temperature, water vapor, wind, and precipitation forecast. Changes in the modeled dynamics and an impact on the precipitation forecast are found. A positive effect on the forecast of the precipitation is found for structures at the model grid scale or larger (1 km), whereas a negative effect is found on convective cells at the subgrid scale that develops within 1 h time intervals. The computation of statistical indices shows that the InSAR assimilation improves the forecast of weak to moderate precipitation ( ${ ).

THE NUCLEAR NEAR-INFRARED SPECTRAL PROPERTIES OF NEARBY GALAXIES

We present spectra of the nuclear regions of 50 nearby (D = 1 - 92 Mpc, median = 20 Mpc) galaxies of morphological types E to Sm. The spectra, obtained with the Gemini Near-IR Spectrograph on the Gemini North telescope, cover a wavelength range of approximately 0.85-2.5 microns at R~1300--1800. There is evidence that most of the galaxies host an active galactic nucleus (AGN), but the range of AGN luminosities (log (L2-10 keV [erg/s]) = 37.0-43.2) in the sample means that the spectra display a wide variety of features. Some nuclei, especially the Seyferts, exhibit a rich emission-line spectrum. Other objects, in particular the type 2 Low Ionisation Nuclear Emission Region galaxies, show just a few, weak emission lines, allowing a detailed view of the underlying stellar population. These spectra display numerous absorption features sensitive to the stellar initial mass function, as well as molecular bands arising in cool stars, and many other atomic absorption lines. We compare the spectra of subsets of galaxies known to be characterised by intermediate-age and old stellar populations, and find clear differences in their absorption lines and continuum shapes. We also examine the effect of atmospheric water vapor on the signal-to-noise ratio achieved in regions between the conventional NIR atmospheric windows, of potential interest to those planning observations of redshifted emission lines or other features affected by telluric H2O. Further exploitation of this data set is in progress, and the reduced spectra and data reduction tools are made available to the community.

Validation of the “HY-2” altimeter wet tropospheric path delay correction based on radiosonde data

Wet tropospheric path delay (PD) is a highly variable term for the altimeter measurement of a sea surface height, caused by the refraction effect of atmospheric water vapor and cloud liquid water. In order to estimate PD values, the “HY-2” system includes a calibration microwave radiometer (CMR) operating at 18.7, 23.8 and 37 GHz. The PD data of the CMR were compared and validated by coincident radiosonde profiles from ten globally distributed radiosonde stations during October 2011 to August 2012. The temporal interval was 1 h. In order to avoid land contamination, different spatial intervals between these two data sets were tested. The empirical fit function of PD uncertainty and spatial interval was found and extrapolated to the ideal situation that the data of CMR and radiosonde were totally coincident. The stability of the brightness temperature of the CMR and its impact on the PD correction was also studied. Consequently, the uncertainty of the PD algorithm of the CMR was estimated to be 2.1 cm.

Effect of atmospheric water vapor on photosynthesis, transpiration and canopy conductance: A case study in corn

The effect of atmospheric water vapor (AV) on plants has mostly been neglected in climate impact studies. The objectives of this study were to determine the effect of AV on photosynthesis (P<sub>n</sub>), dry matter production (DM), transpiration (T<sub>r</sub>), leaf conductance (g<sub>l</sub>) and water use efficiency (WUE), in climate controlled chambers. The relative humidity (RH) was held near 30, 60, and 85%. DM and WUE increased with RH. δDM/δRH ~ 0.3 from 30% to 60% and ~2.2 from 60% to 85%, δWUE/δRH ~0.2 for all RH’s. The improved WUE at a rate of 0.2 units for each percent of increased RH resulted from a synergy between larger g<sub>l</sub> and lower T<sub>r</sub> at high RH. This conclusions carries a bleak message to dry regions.

The Effect of Atmospheric Water Vapor on Neutron Count in the Cosmic-Ray Soil Moisture Observing System

Abstract The cosmic-ray method for measuring soil moisture, used in the Cosmic-Ray Soil Moisture Observing System (COSMOS), relies on the exceptional ability of hydrogen to moderate fast neutrons. Sources of hydrogen near the ground, other than soil moisture, affect the neutron measurement and therefore must be quantified. This study investigates the effect of atmospheric water vapor on the cosmic-ray probe signal and evaluates the fast neutron response in realistic atmospheric conditions using the neutron transport code Monte Carlo N-Particle eXtended (MCNPX). The vertical height of influence of the sensor in the atmosphere varies between 412 and 265 m in dry and wet atmospheres, respectively. Model results show that atmospheric water vapor near the surface affects the neutron intensity signal by up to 12%, corresponding to soil moisture differences on the order of 0.10 m3 m−3. A simple correction is defined to identify the true signal associated with integrated soil moisture that rescales the measured neutron intensity to that which would have been observed in the atmospheric conditions prevailing on the day of sensor calibration. Use of this approach is investigated with in situ observations at two sites characterized by strong seasonality in water vapor where standard meteorological measurements are readily available.

Spectral Compatibility of the NDVI Across VIIRS, MODIS, and AVHRR: An Analysis of Atmospheric Effects Using EO-1 Hyperion

We evaluated the cross-sensor compatibilities of the normalized difference vegetation index (NDVI) across the Visible/Infrared Imager/Radiometer Suite (VIIRS), Moderate Resolution Imaging Spectroradiometer (MODIS), and the National Oceanic and Atmospheric Administration (NOAA)-14 and NOAA-19 Advanced Very High Resolution Radiometer (AVHRR) (AVHRR/2 and AVHRR/3) bandpasses using a global set of Earth Observing One Hyperion hyperspectral data. Five levels of atmospheric correction were simulated to examine the impact of the atmosphere on intersensor NDVI compatibility. These were the uncorrected “top-of-atmosphere”; Rayleigh (RAY); Rayleigh and ozone (RO); Rayleigh, ozone, and water vapor (ROW); and total atmosphere-corrected “top-of-canopy (TOC)” reflectances. Among all possible sensor pairs examined, the highest compatibility was observed for VIIRS versus MODIS. Cross-sensor NDVI relationships between the two sensor bandpasses remained nearly the same throughout all levels of atmospheric correction. AVHRR/3-versus-AVHRR/2 NDVI relationships changed very little and also showed an equivalent level of compatibility to VIIRS versus MODIS across all levels of atmospheric correction although they were subject to systematic differences. Intersensor NDVI compatibilities of VIIRS and MODIS to AVHRR/2 and to AVHRR/3 were lower due primarily to the differential sensitivities of these sensors' near-infrared bands to the atmospheric water vapor effects. Comparisons of cross-sensor NDVI compatibilities where operational atmospheric correction schemes were assumed for each of the sensors suggest the need of VIIRS TOC NDVI for long-term continuity with MODIS and AVHRR, which is not currently produced as part of the standard VIIRS Vegetation Index Environmental Data Record.

On the accuracy of integrated water vapor observations and the potential for mitigating electromagnetic path delay error in InSAR

Abstract. A field campaign was carried out in the framework of the Mitigation of Electromagnetic Transmission errors induced by Atmospheric Water Vapour Effects (METAWAVE) project sponsored by the European Space Agency (ESA) to investigate the accuracy of currently available sources of atmospheric columnar integrated water vapor measurements. The METAWAVE campaign took place in Rome, Italy, for the 2-week period from 19 September to 4 October 2008. The collected dataset includes observations from ground-based microwave radiometers and Global Positioning System (GPS) receivers, from meteorological numerical model analysis and predictions, from balloon-borne in-situ radiosoundings, as well as from spaceborne infrared radiometers. These different sources of integrated water vapor (IWV) observations have been analyzed and compared to quantify the accuracy and investigate the potential for mitigating IWV-related electromagnetic path delay errors in Interferometric Synthetic Aperture Radar (InSAR) imaging. The results, which include a triple collocation analysis accounting for errors inherently present in every IWV measurements, are valid not only to InSAR but also to any other application involving water vapor sensing. The present analysis concludes that the requirements for mitigating the effects of turbulent water vapor component into InSAR are significantly higher than the accuracy of the instruments analyzed here. Nonetheless, information on the IWV vertical stratification from satellite observations, numerical models, and GPS receivers may provide valuable aid to suppress the long spatial wavelength (>20 km) component of the atmospheric delay, and thus significantly improve the performances of InSAR phase unwrapping techniques.

MERIS Atmospheric Water Vapor Correction Model for Wide Swath Interferometric Synthetic Aperture Radar

A major source of error for repeat-pass interferometric synthetic aperture radar is the phase delay in radio signal propagation through the atmosphere, particularly the part due to tropospheric water vapor. These effects become more significant for ScanSAR observations due to their wider coverage (e.g., 400 km <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\times$</tex></formula> 400 km for ENVISAT Advanced Synthetic Aperture Radar (ASAR) wide swath (WS) mode versus 100 km <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\times$</tex></formula> 100 km for ASAR image mode). In this letter, we demonstrate for the first time that a Medium Resolution Imaging Spectrometer water vapor correction model can significantly reduce atmospheric water vapor effects on ASAR WS interferograms, with the phase variation in non-deforming areas decreasing from 3.8 cm before correction to 0.4 cm after correction.

Effect of Atmospheric Water Vapor on the Thermally Induced Crystallization in Zirconia Gel

Effect of water vapor on the thermally induced crystallization of tetragonal ZrO2 in hydrous gel precursor was investigated using TG‐DTA under controlled water vapor pressures, p(H2O). Existence of the temperature region for preliminary nucleation in the region lower than that of the crystallization exothermic peak was identified. The rate of preliminary nucleation was largely enhanced by the atmospheric water vapor, resulting in the increase of number of preexisting nuclei for the subsequent growth and the systematic shift of DTA exothermic peak of crystallization to the lower temperatures with increasing p(H2O). From a systematic shift of the DTA exothermic peak depending on the annealing time at a constant temperature, the rate behavior of preliminary nucleation under high p(H2O) was characterized as the constant rate nucleation. By the preannealing treatment in the temperature region of preliminary nucleation under high p(H2O), the number of preexisting nuclei is nearly saturated without any partial crystallization. From a series of DTA exothermic peaks of crystallization recorded by heating the preannealed samples at different heating rates, the apparent activation energy, Ea, for the crystal growth of tetragonal ZrO2 from the preexisting nuclei was estimated to be Ea = 187.3 ± 3.8 kJ mol−1.

Tomographic reconstruction of wet and total refractivity fields from GNSS receiver networks

One of the most attractive scientific issues in the use of GNSS (Global Navigation Satellite System) signals, from a meteorological point of view, is the retrieval of high resolution tropospheric water vapour maps. The real-time (or quasi real-time) knowledge of such distributions could be very useful for several applications, from operative meteorology to atmospheric modelling. Moreover, the exploitation of wet refractivity field reconstruction techniques can be used for atmospheric delay compensation purposes and, as a very promising activity, it could be applied for example to calibrate SAR or Interferometric-SAR (In-SAR) observations for land remote sensing. This is in fact one of the objectives of the European Space Agency project METAWAVE (Mitigation of Electromagnetic Transmission errors induced by Atmospheric Water vapour Effects), in which several techniques are investigated and results were compared to identify a strategy to remove the contribution of water vapour induced propagation delays in In-SAR products. Within this project, the tomographic reconstruction of three dimensional wet refractivity fields from tropospheric delays observed by a local GNSS network (9 dual frequency GPS receivers) deployed over Como area (Italy), during 12–18 October, 2008, was performed. Despite limitations due to the network design, internal consistency tests prove the efficiency of the adopted tomographic approach: the rms of the difference between reconstructed and GNSS observed Zenith Wet Delays (ZWD) are in the order of 4 mm. A good agreement is also observed between our ZWDs and corresponding delays obtained by vertically integrating independent wet refractivity fields, taken by co-located meteorological analysis. Finally, during the observing period, reconstructed vertical wet refractivity profiles evolution reveals water vapour variations induced by simple cloud covering. Even if our main goal was to demonstrate the effectiveness in adopting tomographic reconstruction procedures for the evaluation of propagation delays inside water vapour fields, the actual water vapour vertical variability and its evolution with time is well reproduced, demonstrating also the effectiveness of the inferred 3D wet refractivity fields.

Integration of InSAR Time-Series Analysis and Water-Vapor Correction for Mapping Postseismic Motion After the 2003 Bam (Iran) Earthquake

Atmospheric water-vapor effects represent a major limitation of interferometric synthetic aperture radar (InSAR) techniques, including InSAR time-series (TS) approaches (e.g., persistent or permanent scatterers and small-baseline subset). For the first time, this paper demonstrates the use of InSAR TS with precipitable water-vapor (InSAR TS + PWV) correction model for deformation mapping. We use MEdium Resolution Imaging Spectrometer (MERIS) near-infrafred (NIR) water-vapor data for InSAR atmospheric correction when they are available. For the dates when the NIR data are blocked by clouds, an atmospheric phase screen (APS) model has been developed to estimate atmospheric effects using partially water-vapor-corrected interferograms. Cross validation reveals that the estimated APS agreed with MERIS-derived line-of-sight path delays with a small standard deviation (0.3-0.5 cm) and a high correlation coefficient (0.84-0.98). This paper shows that a better TS of postseismic motion after the 2003 Bam (Iran) earthquake is achievable after reduction of water-vapor effects using the InSAR TS + PWV technique with coincident MERIS NIR water-vapor data.