Search results for "Remote sensing"

Studies on mineral dust using airborne lidar, ground-based remote sensing, and in situ instrumentation

2018

In August 2015, the AER-D campaign made use of the FAAM research aircraft based in Cape Verde, and targeted mineral dust. First results will be shown here. The campaign had multiple objectives: (1) lidar dust mapping for the validation of satellite and model products; (2) validation of sunphotometer remote sensing with airborne measurements; (3) coordinated measurements with the CATS lidar on the ISS; (4) radiative closure studies; and (5) the validation of a new model of dustsonde.

Holographic in-situ measurements of the spatial droplet distribution in stratiform clouds

1998

Ground based in-situ measurements on the small-scale structure of low-level stratiform clouds have been performed utilizing the HOlographic Droplet and Aerosol Recording system (HODAR) of the University of Mainz, Germany. 6 holograms recorded during stratus cloud events on the Kleiner Feldberg Taunus Mountain Observatory (Frankfurt, Germany) were reconstructed in the laboratory and analysed by means of an automated data extraction and image processing system. In post-processing, each originally recorded droplet population was subjected to 2 statistical methods: (1) the sub-cell scanning analyses with statistical “Fishing” tests and (2) measurements of inter-droplet distance frequency distri…

In situ and lidar observations of tropopause subvisible cirrus clouds during TC4

2010

[1] During the Tropical Composition, Clouds, and Climate Coupling (TC4) experiment in July–August 2007, the NASA WB-57F and ER-2 aircraft made coordinated flights through a tropopause subvisible cirrus (SVC) layer off the Pacific Coast of Central America. The ER-2 aircraft was equipped with a remote sensing payload that included the cloud physics lidar (CPL). The WB-57F payload included cloud microphysical and trace gas measurements, and the aircraft made four vertical profiles through the SVC layer shortly after the ER-2 flew over. The in situ and remotely sensed data are used to quantify the meteorological and microphysical properties of the SVC layer, and these data are compared to the l…

Validation of Collection 6 MODIS land surface temperature product using in situ measurements

2019

Land surface temperature (LST) is an important physical quantity at the land-atmosphere interface. Since 2016 the Collection 6 (C6) MODIS LST product is publicly available, which includes three refinements over bare soil surfaces compared to the Collection 5 (C5) MODIS LST product. To encourage the use of the C6 MODIS LST product in a wide range of applications, it is necessary to evaluate the accuracy of the C6 MODIS LST product. In this study, we validated the C6 MODIS LST product using temperature-based method over various land cover types, including grasslands, croplands, cropland/natural vegetation mosaic, open shrublands, woody savannas, and barren/sparsely vegetated. In situ measurem…

Statistical evaluation of aerosol retrievals from AERONET using in-situ aircraft measurements

2011

Abstract. Aerosol optical properties were measured by NOAA's Airborne Aerosol Observatory over Bondville, Illinois, during more than two years using a light aircraft. Measured properties included total light scattering, backscattering, and absorption, while calculated parameters included aerosol optical depth (AOD), Ångström exponent, single-scattering albedo, hemispheric backscatter fraction, asymmetry parameter, and submicrometer mode fraction of scattering. The in-situ aircraft measurements are compared here with AERONET measurements and retrievals of the aerosol optical properties at the same location. The comparison reveals discrepancies between the aerosol properties retrieved from AE…

A Split-Window Algorithm for Estimating LST From Meteosat 9 Data: Test and Comparison With Data and MODIS LSTs

2009

The main purpose of this letter is to give an operational algorithm for retrieving the land surface temperature (LST) using the Spinning Enhanced Visible and Infrared Imager data onboard the Meteosat Second Generation (MSG2) satellite. The algorithm is a split-window method using the two thermal infrared channels IR10.8 and IR12.0. The MODTRAN 4.0 code was used to obtain numerical coefficients of the algorithm proposed. The results show that for viewing angles lower than 50deg the algorithm is capable of producing LST with a standard deviation of 0.7 K and a root-mean-square error (rmse) of 1.3 K. The algorithm has been applied to a series of MSG2 images obtained from an MSG antenna system …

In-Situ Measurements of the Cloud Microphysical Structure Using Holography

2007

Feasibility study for a nanosatellite-based instrument for in-situ measurements of radio noise

2015

The radio environment on the earth is heavily affected by manmade sources such as radio transmissions, radars, and the like. The effect is particularly strong at MF frequencies and below, since the signals can propagate large distances via ionospheric bounce. Terrestrial magnetometer measurements have long been used to predict the Kp index, which is related to radio transmission at these ranges. Space weather measurements and models can also predict propagation of MF signals on the ground.

An assessment of the differences between spatial resolution and grid size for the SMAP enhanced soil moisture product over homogeneous sites

2018

Abstract Satellite-based passive microwave remote sensing typically involves a scanning antenna that makes measurements at irregularly spaced locations. These locations can change on a day to day basis. Soil moisture products derived from satellite-based passive microwave remote sensing are usually resampled to a fixed Earth grid that facilitates their use in applications. In many cases the grid size is finer than the actual spatial resolution of the observation, and often this difference is not well understood by the user. Here, this issue was examined for the Soil Moisture Active Passive (SMAP) enhanced version of the passive-based soil moisture product, which has a grid size of 9-km and …

First results towards building up a reliable in situ measurements database for LST algorithm validations using modular WSN: Northern Morocco campaign…

2012

This article presents a new method sensitivity ∼0.1°C for in situ LST measurements. The results of wide in situ LST campaigns carried out during 2009 in four distant and different sites located in northern Morocco are shown: 1 Kasr-Seghir, 2 Targha, 3 Tangier, and 4 Chefchaouen. For this purpose, we used two calibrated radiometers with thermal infrared bands, OSM101 and TESTO845. Finally, during these campaigns, a total of 28,531 measurements were made with the proposed wireless-LST Wi-LST system. The preliminary results show a wide variability of the measurements, which is in total accordance with the heterogeneity of the targets' nature. This is encouraging for we are interested in buildi…