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Air relative humidity is an important variable that influences the dryness of dead fuels directly and live fuels indirectly. Many empirical and physical models have been used to estimate air relative humidity based on in-situ observing stations. However, these stations do not provide continuous measurements of relative humidity at large spatial scale. Alternatively, remote sensing provides data that...
Within the Climate Change Initiative of the European Space Agency a multi-satellite soil moisture product covering the period 1979–2010 was released. In this study we first assess its quality by comparing it with soil moisture from ground-based stations and several land surface model estimates. Secondly, the dynamics in the dataset were assessed using trend analysis and comparisons with ancillary...
Stream flow series analysis is of great importance for watershed management such as water conservation, water quality control etc. How to describe the characteristic of stream flow, particularly quantify stream flow variability, has been the subject of numerous studies. Due to the fact that stream flow process usually suffers from strong natural and anthropogenic disturbances, it is hardly to measure...
To resolve uncertainties in evapotranspiration (ET) estimates caused by the retrieval error of remotely sensed data, this study develops an evaporative fraction (EF) parameterization based on surface energy balance and the assumption of generally invariant EF during the daytime. EF is deduced as a function of temporal change of surface temperatures, temporal change of air temperature, temporal change...
Terrestrial Water Storage (TWS) in the Bhagirathi Ganga and Vishnu Ganga basins is an important hydrologic component for the Ganga River. Improved estimation of TWS in the Bhagirathi Ganga and Vishnu Ganga basins is crucial for water resources management for India. Despite its importance, storage and change of TWS in the study area has not been well studied at a larger scale. In this investigation,...
Seawater salinity measurements are currently being made at L-band (1.413 Ghz) by NASA's Aquarius instrument (on the Aquarius/SAC-D observatory). The goal of Aquarius mission is to measure the salinity of seawater to an accuracy on the order of 0.2 psu; this requires a model function of seawater permittivity with a high accuracy. Since 2011, the George Washington University (GW) has employed a cavity...
This paper aims to characterize spatial and temporal vegetation productivity trends that could be related to land degradation in East Africa. A decade of AQUA/TERRA-Moderate Resolution Imaging Spectroradiometer (MODIS) satellite observations on vegetation chlorophyll activity, or Normalized Differential Vegetation Index (NDVI) data, and 25-km rainfall data from the TRMM passive radar instrument were...
Aquarius is an L-band instrument designed to map sea surface salinity from space. Monitoring salinity from space is a particularly sensitive measurement and RFI is a concern, even in the protected band at 1.4 GHz where the Aquarius radiometers operate. To protect against RFI, the Aquarius radiometer samples rapidly and a glitch detection algorithm is employed to check each sample for RFI. This strategy...
Climate change is closely related to trends and fluctuations. Assessing the consequences of these changes to terrestrial ecosystems requires an understanding of the action mechanism of these fractions, respectively. This study examined 11 years of remotely sensed-derived net primary productivity (NPP) to identify the impacts of the trends and fluctuations of temperature change on ecosystem productivity...
Remote sensing of atmospheric CO2 is essential to study global warming. To date, there are many instruments to detect CO2 from space, such as, AIRS, GOSAT, SCIAMACHY and IASI etc., while quantification of the differences among these CO2 products has not been fully investigated yet. In this study, the differences between CO2 products from AIRS, GOSAT, SCIAMAMCHY (totally four products) have been compared...
The objective of this research is to determine the suitability of Worldview-2 high resolution multispectral data in classifying and mapping benthic habitats, specifically seagrass. Worldview-2 offers an increased number of spectral bands for high-resolution image, from the traditional 4bands to 8 bands. It boasts of the ability to enhance mapping and monitoring of benthic habitats with the addition...
The paper explored a method to obtain accurate lake surface heights using Global Navigation Satellite System (GNSS) Coarse/Acquisition Code (C/A)reflected from the ocean surface. The method is referred to as Global Navigation Satellite System-Reflection (GNSS-R) (C/A) code altimetry. It focuses on the extraction of the delay between the direct and reflected signal and inverting ocean altimetry with...
A design of a magnetometer sensor as a combination of three multiturn mutually orthogonal cylindrical coils on a ferromagnetic core in a form of six-arm 3D-cross is considered. The simulation results of the receiving setup of the magnetometer sensor under a homogeneous magnetic field are presented. An impact of the ferromagnetic core on the magnetic field distribution near the body of magnetic sensor...
Electromagnetic induction (EMI) systems often use separate transmit and receive coils. In these systems, it is desirable for the transmit and receive coils to have both minimal mutual coupling and a maximum field product, thus maximizing the detection depth. A mathematical representation is chosen for a pair of spiral coils that allows the coils to be optimized using an iterative convex method. This...
We develop a new methodology to calibrate geophones based on audio sources. A suitable low-frequency loudspeaker reproduces a frequency sweep, it is sensed by the geophone and then it is recorded by a seismograph. The recording is then transformed to the frequency space and compared with a reference frequency response. Although this procedure is not intended for rigorous calibrations, it is a cheap...
This study is focused on electro-optical imaging techniques and analysis that support warning receiver systems in detecting threats. These systems were enabled to receive threat signals, which are generalized to be additive in nature (signal + noise) [1]. The sources of the noise were identified as man-made noise. This, include the humming of the system's power supply in a radio receiver, feedback...
Spaceborne synthetic aperture radar (SAR) has been proved highly significant for remote sensing of the Earth. The image quality is constrained by the system design and the image processing technology, azimuth ambiguity is one of the most important factors. We know the pulse repetition frequency (PRF) determine the sampling rate of the azimuth, but the spectrum of the azimuth is non-bandlimited, it...
In Qinghai-Tibet Plateau, permafrost is usually full of ice underground and sensitive to the temperature. So due to the global warming and seasonal change of temperature, great changes of surface in physical characteristics would occur in the temporal dimension. This could lead to the decorrelation between two SAR images, and hinder the application of Interferometric Synthetic Aperture Radar (InSAR)...
Ship detection is an important application in remote sensing and Earth observation since last century. Properties of ship targets changed greatly as observation accuracy of SAR sensors is strongly increased. Ship targets become objects detailed in structure by contrast to point targets in lower resolution SAR images. In this paper, we present a radiometric-spatial analysis (RSA) based method for ship...
Both the modulation of short wind wave breaking in the long surface wave field and the occurrence of breaking in the presence of a long wave were investigated in wind-wave tank. Short wind waves were generated by the air flow at various speeds, the long surface wave at various frequency and amplitude were generated by wave maker. Data of X- and Ka-band scatterometers, string wave recorder placed in...
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