Search results for "Remote Sensing"

The novel HALO mini-DOAS instrument: inferring trace gas concentrations from airborne UV/visible limb spectroscopy under all skies using the scaling …

2017

Abstract. We report on a novel six-channel optical spectrometer (further on called mini-DOAS instrument) for airborne nadir and limb measurements of atmospheric trace gases, liquid and solid water, and spectral radiances in the UV/vis and NIR spectral ranges. The spectrometer was developed for measurements from aboard the German High-Altitude and Long-Range (HALO) research aircraft during dedicated research missions. Here we report on the relevant instrumental details and the novel scaling method used to infer the mixing ratios of UV/vis absorbing trace gases from their absorption measured in limb geometry. The uncertainties of the scaling method are assessed in more detail than before for …

Discriminating irrigated and rainfed olive orchards with thermal ASTER imagery and DART 3D simulation

2009

Article in Press

Comparing airborne and satellite retrievals of cloud optical thickness and particle effective radius using a spectral radiance ratio technique: two c…

2018

Solar radiation reflected by cirrus and deep convective clouds (DCCs) was measured by the Spectral Modular Airborne Radiation Measurement System (SMART) installed on the German High Altitude and Long Range Research Aircraft (HALO) during the Mid-Latitude Cirrus (ML-CIRRUS) and the Aerosol, Cloud, Precipitation, and Radiation Interaction and Dynamic of Convective Clouds System – Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud Resolving Modelling and to the Global Precipitation Measurement (ACRIDICON-CHUVA) campaigns. On particular flights, HALO performed measurements closely collocated with overpasses of the Moderate Resolution Imaging Spectroradiometer (…

Microphysical and radiative characterization of a subvisible midlevel Arctic ice cluod by airborne observations - a case study

2009

During the Arctic Study of Tropospheric Aerosol, Clouds and Radiation (ASTAR) campaign, which was conducted in March and April 2007, an optically thin ice cloud was observed south of Svalbard at around 3 km altitude. The microphysical and radiative properties of this particular subvisible midlevel cloud were investigated with complementary remote sensing and in situ instruments. Collocated airborne lidar remote sensing and spectral solar radiation measurements were performed at a flight altitude of 2300 m below the cloud base. Under almost stationary atmospheric conditions, the same subvisible midlevel cloud was probed with various in situ sensors roughly 30 min later. <br><br> …

2018

Abstract. Detailed measurements of radiation, atmospheric and aerosol properties were carried out in summer 2013 during the Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region (ADRIMED) campaign in the framework of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx) experiment. This study focusses on the characterization of infrared (IR) optical properties and direct radiative effects of mineral dust, based on three vertical profiles of atmospheric and aerosol properties and IR broadband and narrowband radiation from airborne measurements, made in conjunction with radiosonde and ground-based observations at Lampedusa, in the central Mediterranean. Satell…

Coastal zone water quality: Calibration of a water-turbidity equation for MODIS data

2013

AbstractA nephelometric turbidity algorithm has been specifically calibrated for coastal waters in Sicily. To this purpose, intensive field campaigns were performed in July, August and September 2008. Measurements were collected in situ in three different gulfs. Statistical analysis suggests that field data should be spatially grouped but temporally separated; hence, new calibration parameters have been proposed.Turbidity retrieved by applying the algorithm using literature coefficients and the ones calibrated in situ are shown and compared. The comparison demonstrated that a specific calibration was necessary for quantitatively monitoring turbidity in Sicilian gulfs.

Retrieval of atmospheric CH4profiles from Fourier transform infrared data using dimension reduction and MCMC

2016

We introduce an inversion method that uses dimension reduction for the retrieval of atmospheric methane (CH4) profiles. Uncertainty analysis is performed using the Markov chain Monte Carlo (MCMC) statistical estimation. These techniques are used to retrieve CH4 profiles from the ground-based spectral measurements by the Fourier Transform Spectrometer (FTS) instrument at Sodankyla (67.4 degrees N, 26.6 degrees E), Northern Finland. The Sodankyla FTS is part of the Total Carbon Column Observing Network (TCCON), a global network that observes solar spectra in near-infrared wavelengths. The high spectral resolution of the data provides approximately 3 degrees of freedom about the vertical struc…

A network of magnetometers for multi-scale urban science and informatics

2018

The magnetic signature of an urban environment is investigated using a geographically distributed network of fluxgate magnetometers deployed in and around Berkeley, California. The system hardware and software are described and initial operations of the network are reported. The sensors measure vector magnetic fields at a 3960 Hz sample rate and are sensitive to 0.1 nT/Hz. Data from individual stations are synchronized to ±120 µs using global positioning system (GPS) and computer system clocks and automatically uploaded to a central server. We present the initial observations of the network and preliminary efforts to correlate sensors. A wavelet analysis is used to stud…

Sentinel-3/FLEX Biophysical Product Confidence Using Sentinel-2 Land-Cover Spatial Distributions

2021

The estimation of biophysical variables from remote sensing data raises important challenges in terms of the acquisition technology and its limitations. In this way, some vegetation parameters, such as chlorophyll fluorescence, require sensors with a high spectral resolution that constrains the spatial resolution while significantly increasing the subpixel land-cover heterogeneity. Precisely, this spatial variability often makes that rather different canopy structures are aggregated together, which eventually generates important deviations in the corresponding parameter quantification. In the context of the Copernicus program (and other related Earth Explorer missions), this article propose…

Exploring the Validity of the Long-Term Data Record V4 Database for Land Surface Monitoring

2016

A new version of the long-term data record (LTDR)—Version 4—has been released recently by NASA. This database includes daily information for all advanced very high resolution radiometer channels, as well as ancillary data, from July 1981 up to present. This dataset is the longest available record of remotely sensed data useful for land surface monitoring, since it allows the daily estimation of vegetation indices, as well as the estimation of land surface temperature (LST). Here, we analyze the fitness of this database for land surface monitoring, especially as regards long-term trends and their validity. To that end, we estimated normalized difference vegetation index (NDVI), LST, as well …