Development of a daily soil moisture product for the period of2002–2011 in Chinese mainland

Soil moisture is an essential climate variable(ECV) concerned widely. Due to its high spatial variability, it is costly to measure soil moisture at tens of kilometers scale. In this study, a ten-year(2002–2011) daily soil moisture dataset at 0.25° spatial resolution for Chinese mainland was produced through assimilating the Advanced Microwave Scanning Radiometer for Earth Observing System(AMSR-E) brightness temperature(TB) data into a land surface model(LSM). The obtained soil moisture data was evaluated against soil moisture-measuring networks deployed in two wet areas and one dry area of the Tibetan Plateau.The results show that for the wet areas the accuracy of the soil moisture product obtained from the assimilation is considerably higher than that of both AMSR-E official soil moisture products and land surface simulation results, and for the dry area their accuracy is comparable to each other. The spatial pattern of the soil moisture from the new product is consistent with that of soil porosity from an independent survey-based dataset, further confirming the credibility of the new product. According to this product, the transition regions in China show stronger seasonal variation of soil moisture than dry and wet regions, and drier regions have stronger inter-annual variability of soil moisture than wetter regions, particularly during transitional seasons(spring and autumn). The soil moisture product is accessible at the National Tibetan Plateau Data Center.     

Development of instrumental seismology in Sweden in 1949–1958

Summary A review is given of the present (1959) seismological stations in Sweden, i.e. Uppsala, Kiruna, Skalstugan, and Göteborg, as well as of older stations, which are no longer in operation, i.e. Vassijaure, Abisko, and Lund, including all pertinent information. The disturbing effect of the loose ground at Lund in distinction from the four first-mentioned stations is clearly demonstrated. The very good ground at Uppsala, Kiruna, Skalstugan, and Göteborg, together with the use of modern equipment of high magnification has made these stations, especially Uppsala and Kiruna, very sensitive. This is obvious from the number of recorded earthquakes. The method of time measurements, including direct recording of time signals, is described, and means to reach a high time accuracy are outlined, including the recommendation to use quartz clocks. Long-period (0.5–2 min) disturbances on the long-period Benioff combinations were mainly due to air currents in the seismometer room and were eliminated by providing the seismometers with special covers. The method of ground amplitude determinations is outlined, especially for the Benioff instruments, and typical magnification curves are given. Comparisons of ground amplitudes from simultaneous records of BenioffE, N and WiechertE, N and of BenioffZ and GrenetZ have been made. The amplitude comparison between Benioff and Wiechert has given a new estimate of the effect of friction (especially of the recording pen against the paper) in the Wiechert apparatus.

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Zusammenfassung Eine Übersicht sowohl von den gegenwärtigen (1959) seismologischen Stationen in Schweden, d.h. Uppsala, Kiruna, Skalstugan und Göteborg, als auch von früheren Stationen, die nicht mehr im Betrieb sind, d.h. Vassijaure, Abisko und Lund, wird gegeben. Die störende Wirkung des lockeren Bodens in Lund zum Unterschied gegen die vier erstgenannten Stationen wird deutlich hervorgehoben. Der sehr gute Untergrund in Uppsala, Kiruna, Skalstugan und Göteborg und die Verwendung moderner Apparate hoher Vergrösserung haben diese Stationen, besonders Uppsala und Kiruna, sehr empfindlich gemacht. Dieser Umstand geht aus der Anzahl registrierter Beben hervor. Die Methode der Zeitmessungen (direkte Registrierung der Zeitsignale einbegriffen) wird beschrieben, und Massnahmen eine hohe Zeitgenauigkeit zu erreichen werden erwähnt, die auch die Verwendung von Quarz-Uhren umfassen. Langperiodische Störungen (Perioden 0.5–2 Min) auf den langperiodischen Benioff-Registrierungen waren hauptsächlich durch Luftströmungen im Seismometerraum verursacht und wurden durch spezielle Kappen über den Seismometern eliminiert. Die Methode der Bestimmung von Boden-Amplituden wird beschrieben, hauptsächlich für die Benioff-Instrumente, und typische Vergrösserungskurven sind gegeben. Vergleichungen der Bodenamplituden von parallelen Registrierungen von BenioffE, N und WiechertE, N und von BenioffZ und GrenetZ sind ausgeführt worden. Die Amplitudenvergleichung zwischen Benioff und Wiechert hat eine neue Schätzung des Einflusses der Reibung (speziell vom Schreibfeder gegen das Papier) im Wiechert-Seismographen gegeben.

     

Convection in anelastic models of the Earth’s liquid core

The effects of adiabatic cooling on the convection in the anelastic model of the liquid core of the Earth are considered. It is shown that even minor adiabatic cooling causes significant changes in the pattern of the convection, shifting the peak in the convection intensity to the inner part of the core. Just as in the Boussinesq model, both direct and inverse kinetic energy cascades are simultaneously present, and the direct cascade of entropy is observed.     

Plume Mode of Thermal Convection in the Earth’s Mantle

In our previous works, based on numerical models, it was shown that under certain conditions a hot material can rise in portions in the tails of thermal mantle plumes. The spectrum of these pulsations can correspond to the observed spectra of catastrophic hotspot eruptions. Since most of the existing numerical models of thermal convection for the mantle of the present Earth do not reveal these pulsations, in this work, we analyze the physical cause and initiation conditions of pulsations of thermal plumes. The results of a numerical solution of the thermal convection equations for a material with varying parameters in the extended Boussinesq approximation are presented. It is shown how the structure of the convection is transformed with the increase of convection intensity. At the Rayleigh numbers Ra > 10⁶, convection becomes unsteady, and the configuration of the ascending and descending flows changes. The new flow emerging at the mantle bottom acquires a mushroom shape with a head and a tail. After the rise of the plume’s head to the surface, the tail remains in the mantle in the form of a quasi-stationary hot steam. It turns out that at Ra ~ 5 × 10⁷, the thermal mantle plume becomes pulsating and its tail is in fact a heated channel through which the hot material rises in successive portions. At the Rayleigh numbers Ra > 5 × 10⁸, the tail of the thermal plume breaks and the plume becomes a regular conveyor of separate ascending portions of the hot material, which are referred to as thermals. Thus, thermal convection with pulsating plumes takes place at the transitional stage from the regime of quasi-stationary plumes to the regime of thermals.     

Development of FLEMOcs – a new model for the estimation of flood losses in the commercial sector

Abstract

The estimation of flood damage is an important component for risk-oriented flood design, risk mapping, financial appraisals and comparative risk analyses. However, research on flood-loss modelling, especially in the commercial sector, has not gained much attention so far. Therefore, extensive data about flood losses were collected for affected companies via telephone surveys after the floods of 2002, 2005 and 2006 in Germany. Potential loss determining factors were analysed. The new Flood Loss Estimation MOdel for the commercial sector (FLEMOcs) was developed on the basis of 642 loss cases. Losses are estimated depending on water depth, sector and company size as well as precaution and contamination. The model can be applied to the micro-scale, i.e. to single production sites as well as to the meso-scale, i.e. land-use units, thus enabling its countrywide application.

Citation Kreibich, H., Seifert, I., Merz, B. & Thieken, A. H. (2010) Development of FLEMOcs – a new model for the estimation of flood losses in the commercial sector. Hydrol. Sci. J. 55(8), 1302–1314.     

Electrical Conductivity and Fluid Distribution in the Koryak–Kamchatka Region

Izvestiya, Physics of the Solid Earth - Abstract—The three-dimensional (3D) interpretation of magnetotelluric (MT) data in the Koryak–Kamchatka region with interactive fitting of 3D...     

Effect of Long-Term Variations in Wind Regime over Caspian Sea Region on the Evolution of Its Level in 1948–2017

Water Resources - The data of atmospheric reanalysis NCEP/NCAR over 1948–2017 (R-1) and NCEP/DOE over 1979–2017 (R-2) have been used to show that variations of the Caspian Sea level are...     

Comparison of an artificial neural network and a conceptual rainfall–runoff model in the simulation of ephemeral streamflow

ABSTRACT

The rainfall–runoff process is governed by parameters that can seldom be measured directly for use with distributed models, but are rather inferred by expert judgment and calibrated against historical records. Here, a comparison is made between a conceptual model (CM) and an artificial neural network (ANN) for their ability to efficiently model complex hydrological processes. The Sacramento soil moisture accounting model (SAC-SMA) is calibrated using a scheme based on genetic algorithms and an input delay neural network (IDNN) is trained for variable delays and hidden layer neurons which are thoroughly discussed. The models are tested for 15 ephemeral catchments in Crete, Greece, using monthly rainfall, streamflow and potential evapotranspiration input. SAC-SMA performs well for most basins and acceptably for the entire sample with R² of 0.59–0.92, while scoring better for high than low flows. For the entire dataset, the IDNN improves simulation fit to R² of 0.70–0.96 and performs better for high flows while being outmatched in low flows. Results show that the ANN models can be superior to the conventional CMs, as parameter sensitivity is unclear, but CMs may be more robust in extrapolating beyond historical record limits and scenario building.

EDITOR M.C. Acreman; ASSOCIATE EDITOR not assigned     

Transient Electric Field in the Mesosphere above a Γ-shape Lightning Stroke

We describe the space–time distribution of the pulsed electric field in the middle atmosphere above a positive Γ-shaped lightning stroke. The channel of such a discharge contains a vertical and a horizontal section. The current wave moves initially vertically and then turns horizontally so that radiation appears from the vertical electric dipole followed by that from the horizontal dipole. Combined with reflection from the perfectly conducting ground, the source provides three subsequent pulses in the atmosphere, with the lag being determined by the finite velocity of the current wave in the Γ-shaped stroke. The pulses are reproduced by reflections from the air-ground and the air-ionosphere interfaces and the waveform resembles the M-component, which is often noted in the negative strokes (e.g. Yashunin et al., J Geophys Res 112:D10109, 2007). The non-stationary fine structure appears in the spatial distribution of electric field, which persists for 2 ms or even more and exceeds the runaway electron threshold. Estimates support the idea of free electron bunching in the mesosphere by the pulsed electric field. Focusing may occur about 10 km away from the point of electron- field interaction; it is delayed by a few ms from the moment of interaction. The data presented might be helpful in realistic modeling of the red sprite formation.     

A layer of an unstable seismotectonic strain as an analog of a waveguide at depths of 12–20 km in the Earth’s crust of the Tajik depression

The existence of a layer of unstable seismotectonic strain, which spatially coincides with the waveguide previously detected here at depths of 12–20 km, is established in the central part of the Tajik Depression [Lukk et al., 1970; Nersesov and Chepkunas, 1970; 1971]. This crustal layer is assumed to be weakened and saturated by fluid. The latter is supposedly achieved due to the supply of the liquid component from the bottom crust or upper mantle in the cracks and pores of the waveguide material. A near vertical pillar-like seismogenic body revealed in the work [Shevchenko et al., 2011], which penetrates the waveguide in the depth interval 0–40 km, is considered as one of the possible channels of such inflow. The detected loosened layer (the waveguide) is characterized by a signficant reduction in seismic activity. However, no such reduction is observed within the pillar-like seismogenic body at these depths. Moreover, compared to the nearest ambient environment, the upper 10–15 km of this body feature considerably increased seismic activity that manifested itself in a series of 13 strong earthquakes (with M ≥ 4.7) that occurred within the past approximately 100 years.     

Characteristics of the Activity of the Lintong-Chang＇an Fault in the Late Pleistocene

Analysis of fault outcrops and trench sections indicates fault displacements of 0.2m - 6.0 m on the bottom paleosol layer of the Epipleistocene with the maximum rate of 0.047 mm/a and an average displacement of 1.1 meters. The activity appears as fissures on the fault surface in the late Epipleistocene and there is no obvious displacement. The fault activity is weak and the most active segment is the Bailuyuan segment.     

Reversals of the Geomagnetic Field: Constraint on Convection Intensity in the Earth’s Core

Geomagnetism and Aeronomy - Modern geodynamo models allow the generation of a magnetic field without reversals and with frequent reversals. The transition from one regime to another is associated...     

Generation of a burst of geomagnetic pulsations in the 1–3 Hz frequency range in the daytime sector as a result of dramatic increases in the solar wind dynamic pressure

The spatio-temporal evolution of geomagnetic pulsation bursts at frequencies of 1–3 Hz, observed at the Mondy (MLT ≈ 1200; M_lat = 46.8°; L = 2.16) and Borok (MLT ≈ 0820; M_lat = 54.0°; L = 2.94) midlatitude observatories and Lovozero auroral observatory (MLT ≈ 0820; M_lat = 64.2°; L = 5.36), has been studied. The considered bursts were registered in daytime sector of the magnetosphere after sudden impulses (SIs) caused by dramatic increases in the solar wind dynamic pressure and registered on board the WIND satellite. The SI onset time corresponds to the Sc* time shown in the Geomagnetic Indices Bulletin. The possible relationship between the excitation of these bursts and the variations in the particle partial density in the range of energies 0.03–45 keV per unit charge has been studied. The bursts were registered on board the LANL geosynchronous satellites. A comparison of the particle partial density variations measured on the satellites and the variation temperature anisotropy (A = T_⊥/T_‖ − 1) with the variations in the pulsation burst amplitude on the ground indicated that the partial density maximum and the minimum (A ≤ 0) of the electron temperature anisotropy index in the vicinity of local noon coincide in time with the pulsation generation instant. A comparison of the electron partial density variations on the LANL-1994 and LANL-97A geosynchronous satellites spaced in longitude and the spatio-temporal variations in the development of bursts make it possible to assume that 1–3 Hz geomagnetic pulsations are excited in the vicinity of local noon and subsequently propagate along the ionospheric waveguide.     

Impacts of groundwater flow on the evolution of a thermokarst lake in the permafrost–dominated region on the Qinghai–Tibet plateau

As a result of global warming induced permafrost degradation in recent decades, thermokarst lakes in the Qinghai–Tibet plateau (QTP) have been regulating local hydrological and ecological processes. Simulations with coupled moisture–heat numerical models in the Beiluhe basin (located in the hinterland of permafrost regions on the QTP) have provided insights into the interaction between groundwater flow and the freeze–thaw process. A total of 30 modified SUTRA scenarios were established to examine the effects of hydrodynamic forces, permeability, and climate on thermokarst lakes. The results indicate that the hydrodynamic condition variables regulate the permafrost degradation around the lakes. In case groundwater recharges to the lake, a low–temperature groundwater flow stimulates the expansion of the surrounding thawing regions through thermal convection. The thawing rate of the permafrost underlying the lake intensifies when groundwater is discharged from the lake. Under different permeability conditions, spatiotemporal variations in the active layer thickness significantly influence the occurrence of an open talik at the lake bottom. A warmer and wetter climate will inevitably lead to a sharp decrease in the upper limit of the surrounding permafrost, with a continual decrease in the duration of open talik events. Overall, our results underscore that comprehensive consideration of the relevant hydrologic processes is critical for improving the understanding of environmental and ecological changes in cold environments.     

Study of Deep Carbonate Reservoirs in the Desert Areas by Transient Electromagnetic Method

In 1997, the TZ- 162 well in Tazhong area of the Tarim basin hit the lower Paleozoic dolomite reservoir at a depth of 5,900 m. The distribution of the dolomite reservoir, however,was very difficult to delineate due to the complex surface conditions and poor seismic properties. High-precision transient electromagnetic sounding (TEM) was conducted and good results obtained in this area. This paper discussed the principle,data processing and interpretation of this method. The resultsof studying the dolomite reservoirs demonstrated the effectiveness of the method in studying the low-resistance dolomite reservoirs in the high-resistance carbonates. This method should be an effective one to study reservoirs in areas with similar physical properties as well.     

Implementation of a wetting-and-drying model in simulating the Kennebec–Androscoggin plume and the circulation in Casco Bay

A high-resolution coastal ocean model was developed to simulate the temporal/spatial variability of the Kennebec–Androscoggin (K–A) river plume and the circulation in Casco Bay. The model results agree favorably with the moored and shipboard observations of velocity, temperature, and salinity. The surface salinity gradient was used to distinguish the plume from the ambient coastal water. The calculated plume thickness suggests that the K–A plume is surface trapped. Its horizontal scales correlate well with Q ^0.25, where Q is the volume discharge of the rivers. Directional spreading is affected by the wind with the upwelling favorable wind transporting the plume water offshore. Both the wind and the tide also enhance mixing in the plume. The inclusion of a wetting-and-drying (WAD) scheme appears to enhance the mixing and entrainment processes near the estuary. The plume becomes thicker near the mouth of the estuary, the outflow velocity of the plume is weaker, and the radius of the river plume shrinks. The flow field in the model run with the WAD is noisier, not only in shallow areas of Casco Bay but also in the plume and even on the shelf. We speculate that the WAD processes can affect much larger areas than the intertidal zones, especially via a river plume that feeds into a coastal current.     

Development of a 100 MPa water–gas two-phase fluid pressurization device

This paper introduces a 100 MPa water gas twophase fluid pressurization device.The device can provide 100 MPa gas pressure and 200 MPa liquid pressure for small volume(20 mL) high-pressure experimental devices.This device can make the pressure control independent of the temperature control without changing the material components of the system.The resolution of this device in adjusting the pressure is ±0.2 MPa in the process of boosting and depressurizing.This pressure boosting device generates very little vibration during work and it can be used in experiments with strict requirements on vibration.As a thermodynamic parameter,pressure has a great influence on matter.In the field of experimental geochemistry,pressure is not only an experimental method and an extreme condition but an important physical parameter independent of temperature and chemical composition.