Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

Soil Hydraulic and Thermal Properties for Land Surface Modelling over the Tibetan Plateau [version 1]

The in situ measurement of soil (hydraulic and thermal) property profiles were taken across the three climate zones (arid, semi-arid & semi-humid) over the Tibetan Plateau. In each climate zone, 1) the soil was sampled (c.a. 200 g) with a plastic bag used to measure gravel content, soil texture and soil organic content; 2) the soil was sampled with standard sample rings (5cm in height, 100 cm3 in volume) for the determination of bulk density, porosity and thermal conductivity; 3) for deriving the Soil Water Retention Curve (SWRC), a dedicated small sample ring (1 cm in height, 20 cm3 in volume) was used; 4) the in situ Ks was measured using the Aardvark permeameter, a fully automated constant-head borehole permeameter. Using these samples, the laboratory analyses were carried out with reference to standard methods. The quality of dataset was evaluated based on quality indicators from World Soil Information Institute and on cross check using values in the literature. This dataset was further used to evaluate the existing soil datasets over the Tibetan Plateau

An Air-to-Soil Transition Model for Discrete Scattering–Emission Modelling of L-Band Radiometry at Maqu site, the Eastern Tibetan Plateau

In situ ELBARA-III radiometer observations of brightness temperature T_B^p (with p = H, V) in Maqu site, the eastern Tibetan Plateau were used for investigations on roughness effects over natural land surface and on coherent and incoherent emission processes in radiative transfer modelling. Aided by in situ soil moisture (SM) and temperature profile measurments and the MCD15A2H - MODIS/Terra+Aqua Leaf Area Index, the study simulated T_B^p and demonstrated a necessity of an air-to-soil transition (AS) model in incorporating roughness effects for understanding seasonal L-band radiometry. Supported by the in situ meteorological observation data in Maqu site, the applicability and uncertainty of AS-based models in T_B^p simulations were discussed. The meteorological data involve precipitation intensity, air temperature, and albedo with ground temperature, which were derived from the in situ four components radiation measurement (i.e., up- and down-welling shortwave and longwave radiations)

Integrating Remote Sensing Information Into A Distributed Hydrological Model for Improving Water Budget Predictions in Large-scale Basins through Data Assimilation

sensor

HydroThermal Dynamics of Frozen Soils on the Tibetan Plateau during 2015-2016

The hydrothermal dynamics of frozen soil were monitored at a typical meadow ecosystem on the Tibetan Plateau. Soil temperature/moisture profiles were automatically measured at a 30-min. interval by 5TM ECH2O probes (Decagon Devices, Inc., USA) installed at the following depths: 5 cm, 10 cm, 20 cm, 40cm, and 80 cm. The turbulent heat fluxes were measured by an eddy-covariance (EC) system (LI-COR 7500, Campbell Scientific). STEMMUS-FT (Simultaneous Transfer of Energy, Mass and Momentum in Unsaturated Soil with Freeze-Thaw process) model, with two control experiments (Ctrl1 for Van Genuchten hydraulic scheme and Ctrl2 for Clapp and Hornberger hydraulic scheme), was employed to reproduce the simultaneous movement of soil moisture and heat flow in the frozen soil. With the aid of physically based STEMMUS-FT model and in situ measurements, we can investigate the underlying mechanisms of the water and heat transfer in frozen soils

The MSG technique: Improving commercial microwave link rainfall intensity by using rain area detection from meteosat second generation

Commercial microwave link (MWL) used by mobile telecom operators for data transmission can provide hydro-meteorologically valid rainfall estimates according to studies in the past decade. For the first time, this study investigated a new method, the MSG technique, that uses Meteosat Second Generation (MSG) satellite data to improve MWL rainfall estimates. The investigation, conducted during daytime, used MSG optical (VIS0.6) and near IR (NIR1.6) data to estimate rain areas along a 15 GHz, 9.88 km MWL for classifying the MWL signal into wet–dry periods and estimate the baseline level. Additionally, the MSG technique estimated a new parameter, wet path length, representing the length of the MWL that was wet during wet periods. Finally, MWL rainfall intensity estimates from this new MSG and conventional techniques were compared to rain gauge estimates. The results show that the MSG technique is robust and can estimate gauge comparable rainfall estimates. The evaluation scores every three hours of RMSD, relative bias, and r2 based on the entire evaluation period results of the MSG technique were 2.61 mm h−1, 0.47, and 0.81, compared to 2.09 mm h−1, 0.04, and 0.84 of the conventional technique, respectively. For convective rain events with high intensity spatially varying rainfall, the results show that the MSG technique may approximate the actual mean rainfall estimates better than the conventional technique

Comparison of crop classification capabilities of spaceborne multi-parameter SAR data

With the arisen spaceborne multi-parameter Synthetic Aperture Radar (SAR) systems, such as Envisat ASAR, TerraSAR-X, ALOS PALSAR, and RADARSAT-2, the interest of crop mapping has been increasing. The present study compares the capabilities of the multi-parameter SAR in discriminating the main crop types by object-based classification in Haian county of Jiangsu province, South China. Two kinds of information, SAR intensity based and SAR statistical properties based are used for Maximum Likelihood Classification (MLC) and Minimum Distance Classification (MDC) respectively. The results show that, the L-band SAR can uniquely identify mulberry from dryland crops, such as maize and vegetable and C-band SAR has some advantages in mapping rice. Specifically, the polarimetric RADARASAT-2 data can identify the rice with accuracy about 75% ∼ 80% which is similar as the result from X-band TerraSAR-X Spotlight data but higher than that from C-band dual-polarization Envisat ASAR data. Nevertheless, both of X- and C-band can hardly separate the mulberry from the other dry-land crops