Several high-resolution proxy environmental records have been obtained for the last 35 kyr from ODP Hole 658C, a well-studied site ca. 200 km o€ Cap Blanc, NW Africa. The collective assessment based on the marine proxies (U 0 37 SST, contents of TOC and chlorins, Upwelling Radiolarian Index and the percentage of Florisphaera profunda), surprisingly indicates that the last glacial maximum (LGM) ...

Models predict that global warming may increase aridity in water-limited ecosystems by accelerating evapotranspiration. We show that interactions between warming and the dominant biota in a grassland ecosystem produced the reverse effect. In a 2-year field experiment, simulated warming increased spring soil moisture by 5-10% under both ambient and elevated CO2. Warming also accelerated the decl...

The episodic nature of hydrological flows such as surface runoff and preferential flow is a result of the nonlinearity of their triggering and the intermittency of rainfall. In this paper we examine the temporal dynamics of threshold processes that are triggered by either an infiltration excess (IE) mechanism when rainfall intensity exceeds a spec5 ified threshold value, or a saturation excess ...

Aridity conditions in semi-arid lands with warm climates are key variables that must be assessed to properly manage water and plan minimise the threat of desertification. This study analyses spatial distribution aridity Extremadura, southwestern Spain, using De Martonne index (IDM), considering a historical reference period (1971–2005) three-time intervals: 2006–2035 (near future), 2036–2065 (m...

Xinjiang, an arid region of China, has experienced a substantial warming–wetting trend over the past five decades. However, climate change affected vegetation growth/greening in Central Asia unexpected ways due to complex ecological effects. We found significant greening (consistent increase normalized difference index or NDVI) from 1982 1996, during growing season; however, NDVI consequently d...

States of ecological maturity and temporal trends of drylands in Morocco, Algeria and Tunisia north of 28 ̋N are reported for 1998–2008. The input data were Normalized Difference Vegetation Index databases and corresponding climate fields, at a spatial resolution of 1 km and a temporal resolution of one month. States convey opposing dynamics of human exploitation and ecological succession. They ...

Abstract In recent years, greenhouse gas emissions have caused extensive changes in the global climate. Climate change leads to extreme events, such as droughts. The present study investigates precipitation and temperature variations past future drought characteristics Iran through data from 40 synoptic stations 33 general circulation models (GCMs) under RCP4.5 RCP8.5 scenarios. As a first step...

Fairy circles consist of isolated or randomly distributed circular areas devoid of any vegetation. They are observed in vast territories in southern Angola, Namibia and South Africa. We report on the formation of fairy circles, and we interpret them as localized structures with a varying plateau size as a function of the aridity. Their stabilization mechanism is attributed to a combined influen...

The hypothesis of a complementary relationship in regional evapotranspiration allows for estimation of actual evapotranspiration on a regional scale by simple, physically based models that take into account feedbacks in land surface-atmosphere dynamics. A regional, seasonal Advection-Aridity model is used to create a monthly time-series of actual evapotranspiration for a period of 27 years at a...

This study was conducted to determine the potential evapotranspiration (PET) of maize, the crop coefficient (Kc) under full water requirement as well as the cause of decrease in maize yield. It was determined that the seasonal PET of maize is about 486.6 mm. The Kc under full water supply was found to be: 0.11, 0.35, 1.51 and 0.34 for initial, development, midseason and the late season stages r...