Adaptive drift and barrier-avoidance by a fly-forage migrant along a climate-driven flyway

Background Route choice and travel performance of fly-forage migrants are partly driven by large-scale habitat availability, but it remains unclear to what extent wind support through large-scale wind regimes moulds their migratory behaviour. We aimed to determine to what extent a trans-equatorial fly-forage migrant engages in adaptive drift through distinct wind regimes and biomes across Africa. The Inter-tropical Front (ITF) marks a strong and seasonally shifting climatic boundary at the thermal equator, and we assessed whether migratory detours were associated with this climatic feature. Furthermore, we sought to disentangle the influence of wind and biome on daily, regional and seasonal travel performance. Methods We GPS-tracked 19 adult Eleonora’s falcons Falco eleonorae from the westernmost population on the Canary Islands across 39 autumn and 36 spring migrations to and from Madagascar. Tracks were annotated with wind data to assess the falcons’ orientation behaviour and the wind support they achieved in each season and distinct biomes. We further tested whether falcon routes across the Sahel were correlated with the ITF position, and how realized wind support and biome affect daily travel times, distances and speeds. Results Changes in orientation behaviour across Africa’s biomes were associated with changes in prevailing wind fields. Falcons realized higher wind support along their detours than was available along the shortest possible route by drifting through adverse autumn wind fields, but compromised wind support while detouring through supportive spring wind fields. Movements across the Sahel-Sudan zone were strongly associated to the ITF position in autumn, but were more individually variable in spring. Realized wind support was an important driver of daily travel speeds and distances, in conjunction with regional wind-independent variation in daily travel time budgets. Conclusions Although daily travel time budgets of falcons vary independently from wind, their daily travel performance is strongly affected by orientation-dependent wind support. Falcons thereby tend to drift to minimize or avoid headwinds through opposing wind fields and over ecological barriers, while compensating through weak or supportive wind fields and over hospitable biomes. The ITF may offer a climatic leading line to fly-forage migrants in terms of both flight and foraging conditions.

How volcanism impact on the variability of the South American Monsoon System and the associated Atlantic Subtropical Cell

<p>Large volcanic eruptions can affect the global climate through changes in atmospheric and ocean circulation. Understanding the influence of volcanic eruptions on the hydroclimate over monsoon regions is of great scientific and social importance. The South America Monsoon System (SAMS) is the most important climatic feature of the continent. Both the Intertropical and the South Atlantic wind convergence zones (ITCZ and SACZ, respectively) are fundamental components of the SAMS. They show variations on a broad range of scales, dependent on complex multi-system interactions with the adjacent Atlantic Ocean and teleconnections. Also driven by the winds, the Atlantic Subtropical Cell (STC) is the link between the subduction zone in the subtropical gyre with the tropics. Hence, the STC influence equatorial sea surface temperature variability on interannual to decadal scales in the tropical Atlantic Ocean. In order to improve our understanding of the responses of the ocean-atmosphere system to the volcanic forcing, we aim to identify the dominant mechanisms of seasonal-to-interdecadal variability of the SAMS and the Atlantic STC after large Pinatubo-like (1991) and Tambora-like (1815) eruptions relying on the VolMIP model intercomparison project experiments.</p>

Operative Technology Research of Grange's Energy Conservation in the Jilin Province

Combined with climatic feature and peasants economic condition in existence,starting with engery conservation design of grange and analysis of reconstruction technology,the writer briefly expound the operative technology of engery consevation and the reconstruction technology of auld grange,from the point of envelop enclosure,heating system and new energy resource,which is now suitable for the new grange in the Jilin province.

Forecast Skill of the South American Monsoon System

The South American monsoon system (SAMS) is the most important climatic feature in South America and is characterized by pronounced seasonality in precipitation. This study uses the National Centers for Environmental Prediction Climate Forecast System, reforecasts version 2 (CFSRv2), to investigate the skill of probabilistic forecasts of onset and demise dates, duration, and amplitude of SAMS during 1982–2009. A simple index based on the empirical orthogonal function of precipitation anomalies is employed to characterize onsets, demises, durations, and amplitudes of SAMS. The CFSv2 model has useful skill to forecast seasonal changes in SAMS. Probabilistic forecasts of onset and demise dates have 16.5% and 43.3% improvements, respectively, over climatological forecasts. Verification of hindcasts of durations and amplitudes of SAMS shows relatively small biases and root-mean-square errors.

The Distribution of Tsetse-flies in Tanganyika Territory

1. Details are given of the distribution of the eight species of tsetse occurring in the Tanganyika Territory (G. brevipalpis, G. longipennis, G. fuscipleuris, G. palpalis, G. morsitans, G. swynnertoni, G. pallidipes, and G. austeni).2. The effect of past climatic changes on the present distribution of some of the species is discussed in a somewhat speculative manner.3. The detailed information is summarised in a general description and map of the fly-belts of the Territory.4. The effect of certain broad vegetation types and major topographical features on the distribution of species of tsetse in Tanganyika are discussed.5. The effect of the major topographical features in limiting the distribution of the fly is always found to reside in some accompanying vegetative or climatic feature.6. Possible and likely extensions of the fly-belts are briefly indicated ; if these should take place, but little of Tanganyika Territory would remain uninfested by tsetse-fly. The possibility of natural retreat of fly-belts is also discussed.7. A few details are given of the habits and habitats of some of the lesser known species (G. longipennis, G. fuscipleuris and G. austeni).