Observed trends of climate and land cover changes in Lake Baikal basin

Land cover and vegetation in Lake Baikal basin (LBB) are considered to be highly susceptible to climate change. However, there is less information on the change trends in both climate and land cover in LBB and thus less understanding of the watershed sensitivity and adaptability to climate change. Here we identified the spatial and temporal patterns of changes in climate (from 1979 to 2016), land cover, and vegetation (from 2000 to 2010) in the LBB. During the past 40 years, there was a little increase in precipitation while air temperature has increased by 1.4 °C. During the past 10 years, land cover has changed significantly. Herein grassland, water bodies, permanent snow, and ice decreased by 485.40 km², 161.55 km² and 2.83 km², respectively. However, forest and wetland increased by 111.40 km² and 202.90 km², respectively. About 83.67 km² area of water bodies has been converted into the wetland. Also, there was a significant change in Normalized Difference Vegetation Index (NDVI), the NDVI maximum value was 1 in 2000, decreased to 0.9 in 2010. Evidently, it was in the mountainous areas and in the river basin that the vegetation shifted. Our findings have implications for predicting the safety of water resources and water eco-environment in LBB under global change.     

Optical and radiative properties of aerosols over Abu Dhabi in the United Arab Emirates

The present study is on the aerosol optical and radiative properties in the short-wave radiation and its climate implications at the arid city of Abu Dhabi (24.42 ^°N, 54.61 ^°E, 4.5 m MSL), in the United Arab Emirates. The direct aerosol radiative forcings (ARF) in the short-wave region at the top (TOA) and bottom of the atmosphere (BOA) are estimated using a hybrid approach, making use of discrete ordinate radiative transfer method in conjunction with the short-wave flux and spectral aerosol optical depth (AOD) measurements, over a period of 3 years (June 2012–July 2015), at Abu Dhabi located at the south-west coast of the Arabian Gulf. The inferred microphysical properties of aerosols at the measurement site indicate strong seasonal variations from the dominance of coarse mode mineral dust aerosols during spring (March–May) and summer (June–September), to the abundance of fine/accumulation mode aerosols mainly from combustion of fossil-fuel and bio-fuel during autumn (October–November) and winter (December–February) seasons. The monthly mean diurnally averaged ARF at the BOA (TOA) varies from ?13.2 Wm^?2 (～?0.96 Wm^?2) in November to ?39.4 Wm^?2 (?11.4 Wm^?2) in August with higher magnitudes of the forcing values during spring/summer seasons and lower values during autumn/winter seasons. The atmospheric aerosol forcing varies from + 12.2 Wm^?2 (November) to 28.2 Wm^?2 (June) with higher values throughout the spring and summer seasons, suggesting the importance of mineral dust aerosols towards the solar dimming. Seasonally, highest values of the forcing efficiency at the surface are observed in spring (?85.0 ± 4.1 W m^?2 τ ^?1) followed closely by winter (?79.2 ± 7.1 W m^?2 τ ^?1) and the lowest values during autumn season (?54 ± 4.3 W m^?2 τ ^?1). The study concludes with the variations of the atmospheric heating rates induced by the forcing. Highest heating rate is observed in June (0.39 K day ^?1) and the lowest in November (0.17 K day ^?1) and the temporal variability of this parameter is linearly associated with the aerosol absorption index.     

Estimation of chlorophyll fluorescence under natural illumination from hyperspectral data

This paper reports a series of laboratory and field measurements of spectral reflectance under artificial and natural light conditions which demonstrate that effects of natural chlorophyll fluorescence are observable in the reflectance red edge spectral region. These are results from the progress made to link physiologically-based indicators to optical indices from hyperspectral remote sensing in the Bioindicators of Forest Sustainability Project. This study is carried out on twelve sites of Acer saccharum M. in the Algoma Region, Ontario (Canada), where field measurements, laboratory-simulation experiments, and hyperspectral CASI imagery have been carried out in 1997, 1998, 1999 and 2000 campaigns. Leaf samples from the study sites have been used for reflectance and transmittance measurements with the Li-Cor Model 1800 integrating sphere apparatus coupled to an Ocean Optics Model ST1000 fibre spectrometer in which the same leaves are illuminated alternatively with and without fluorescence-exciting radiation. A study of the diurnal change in leaf reflectance spectra, combined with fluorescence measurements with the PAM-2000 Fluorometer show that the difference spectra are consistent with observed diurnal changes in steady-state fluorescence. Small canopies of Acer saccharum M. have been used for laboratory measurements with the CASI hyperspectral sensor, and under natural light conditions with a fibre spectrometer in diurnal trials, in which the variation of measured reflectance is shown experimentally to be consistent with a fluorescence signature imposed on the inherent leaf reflectance signature. Such reflectance changes due to CF are measurable under natural illumination conditions, although airborne experiments with the CASI hyperspectral sensor produced promising but less convincing results in two diurnal experiments carried out in 1999 and 2000, where small variations of reflectance due to the effect of CF were observed.     

Aeromagnetic map constrains cratonization of the Arabian Shield

A new aeromagnetic map together with new geological and geochronological data has led to a reinterpretation of the geological history of the Arabian Shield.
The magnetic anomalies outline an orogenic complex containing a network of mostly left-lateral strike-slip faults, including the Nabitah Belt and several peripheral mountain ranges. Oblique accretion resulted in obliteration of early volcanic-arc magnetic fabrics, which were almost completely replaced by a NW–SE magnetic fabric in the northern Shield; the southern Shield, however, reveals extensive E–W anomalies related to post-accretion magmatic intrusions. This complex web of orogenic zones is intimately associated with synchronous molasse basins that formed 680–610 Ma.
The distribution and chronology of orogenic zones, related to the closing of East and West Gondwana, brings into question several earlier assumptions, such as high continental growth rates, palaeogeodynamic reconstructions, the definitions of the Nabitah and Najd faults, and the significance of molasse basins.     

Lithostratigraphic subdivision of the Kuhlan Formation in Yemen

The lithostratigraphic subdivision of the Kuhlan Formation in Yemen is reviewed based on the previous literature and new examination of five widely spaced outcrops in the Kuhlan Affar, Jabal Maswar, Jabal Salab, Wadi Hajar, and Ras Falanj areas. Following the guidelines set by the North American Commission on Stratigraphic Nomenclature, Kuhlan Formation, with an age as latest Triassic to the Middle Jurassic, includes three members, Azzan, Souq, and Hesn, in an ascending order. Azzan member consists mainly of about 40 m of whitish coarse grained sandstone with many conglomeratic horizons. The Souq member is characterized by its reddish to brownish sandstones as well as the presence of polygonal structures at in the central part of this member, with a thickness of about 70 m. The Hesn member consists dominantly (80 m) of whitish sandstones with some marl intercalations at its topmost part. The Kuhlan Formation was deposited in a fluviatile environment.     

Interprétation hydrogéologique de l'aquifère des bassins sud-rifains (Maroc) : apport de la sismique réflexion

The aquifer of the Rharb Basin is constituted by heterogeneous material. The seismic reflexion interpretation carried out in this area, highlighted a permeable device compartmentalized in raised and subsided blocks. Depressions identified in the northern and southernmost zones are characterized by Plio-Quaternary fillings that are favourable to the hydrogeological exploitation. Two mechanisms contribute to structure the Plio-Quaternary aquifer: the Hercynian reactivation in the southernmost part, and the gravitational mechanism of the Pre-Rifean nappe. The groundwater flow and the aquifer thickening are controlled by this reactivation.     

Research on experiment and calculation of foam bursting device

This research presents experimental data on mechanical foam bursting device,based on the high speed of air fluid impinging insidethe foam bursting device,foam bubbles disrupted as a consequence of pressures changed very quickly as shear force and their impact forces.Experimental data on foam-bursting capacity have been presented.Designed device can provide effective foam bursting on collapse foam.     

A regional analysis of new production on the northwest European shelf using oxygen fluxes and a ship-of-opportunity

Seasonal new production (g C m⁻²) estimates obtained from dissolved oxygen and nitrate concentrations in surface waters (5 m depth) along a track between the UK (Portsmouth) and northern Spain (Bilbao) are compared. An oxygen flux method, in combination with a ship of opportunity (SOO), was tested on the northwest European shelf for its value in distinguishing high production in frontal regions. Dissolved oxygen, nitrate and chlorophyll a samples were collected monthly from February to July 2004, alongside continuous autonomous measurements of salinity, temperature and chlorophyll fluorescence. Depth integrated new production estimates for all the individually analysed hydrographic regions of the route were produced.Results from three widely used gas-exchange parameterizations gave seasonal (February–July) new production estimates of 54–68 g C m⁻² for the Ushant region of the western English Channel and 31–40 g C m⁻² for the shelf slope, averaging 24–31 g C m⁻² for the route. This is double the route average obtained using the nitrate assimilation method (17 g C m⁻²) and within the ranges of previous estimates in the same region. The oxygen flux method gave a fivefold enhancement compared to the nitrate method in the Ushant frontal region and a threefold enhancement in the English Channel and shelf break regions. Determining oxygen fluxes to estimate new production may be more reliable than nitrate assimilation in active tidal or frontal regions of shelves where nitrate may be added to the system post-winter through advection or entrainment.