Simple Biosphere Model version 4.2 (SiB4) technical description

The Simple Biosphere Model (SiB4) is a mechanistic, prognostic land surface model that integrates heterogeneous land cover, environmentally responsive prognostic phenology, dynamic carbon allocation, and cascading carbon pools from live biomass to surface litter to soil organic matter. By combining biogeochemical, biophysical, and phenological processes, SiB4 predicts vegetation and soil moisture states, land surface energy and water budgets, and the terrestrial carbon cycle. Rather than relying on satellite data, SiB4 fully simulates the terrestrial carbon cycle by using the carbon fluxes to determine the above and belowground biomass, which in turn feeds back to impact carbon assimilation and respiration. Every 10-minute time-step, SiB4 computes the albedo, radiation budget, hydrological cycle, layered temperatures, and soil moisture, as well as the resulting energy exchanges, moisture fluxes, carbon fluxes, and carbon pool transfers. Photosynthesis depends directly on environmental factors (humidity, moisture, and temperature) and aboveground biomass; and carbon uptake is determined using enzyme kinetics and stomatal physiology. Carbon release and pool transfers depend on assimilation rate, day length, moisture, phenology, temperature, and pool size. Once daily the net assimilated carbon is allocated to the live pools depending on phenology, soil moisture, and temperature; all live and dead pools are updated, including any necessary carbon transfers between pools; and the land surface state and related properties are revised. The new LAI and pools are then used for sub-hourly assimilation and respiration, completing the carbon cycle and providing self-consistent predicted vegetation states, soil hydrology, carbon pools, and land-atmosphere exchanges

Potential of Pigeon Creek, San Salvador, Bahamas, as Nursery Habitat for Juvenile Reef Fish

This project assessed the significance of Pigeon Creek, San Salvador, Bahamas as a nursery habitat for coral reef fishes. Pigeon Creek’s perimeter is lined with mangrove and limestone bedrock. The bottom is sand or sea grass and ranges in depth from exposed at low tide to a 3-m deep, tide-scoured channel. In June 2006 and January 2007, fish were counted and their maturity was recorded while sampling 112 of 309 possible 50-m transects along the perimeter of the Pigeon Creek. Excluding silversides (Atherinidae, 52% of fish counted), six families each comprised more than 1% of the total abundance (Scaridae/parrotfishes, 35.3%; Lutjanidae/snappers, 23.9%; Haemulidae/grunts, 21.0%; Gerreidae/mojarras, 8.5%; Pomacentridae/damselfishes, 6.1%; Labridae/wrasses, 2.4%). There were few differences in effort-adjusted counts among habitats (mangrove, bedrock, mixed), sections (north, middle, southwest) and seasons (summer 2006 and winter 2007). Red mangrove (Rhizophora mangle), covering 68% of the perimeter was where 62% of the fish were counted. Snappers, grunts and parrot fishes are important food fishes and significant families in terms of reef ecology around San Salvador. Mangrove was the most important habitat for snappers and grunts; bedrock was most important for parrot fishes. The southwest section was important for snappers, grunts and parrot fishes, the north section for grunts and parrot fishes, and the middle section for snappers. Among the non-silverside fish counted, 91.2% were juveniles. These results suggest that Pigeon Creek is an important nursery for the coral reefs surrounding San Salvador and should be protected from potential disturbances

The UK, interrogation and Iraq, 2003-8

The UK’s interrogation operations during the conflict in Iraq (2003-8) are often portrayed by the media as involving significant amounts of mistreatment. The article demonstrates that these practices are not necessarily representative of the UK’s interrogation operations across this conflict. In doing so it contributes to the limited literature on the practice of interrogation and on the UK’s combat operations in Iraq. The UK’s interrogation capability, and therefore its intelligence-gathering capability, is shown to have rested primarily with the military’s Joint Forward Interrogation Team (JFIT). The JFIT suffered from limitations to the number, training and experience of its interrogators and interpreters. It is argued that maintaining a permanent, higher level of preparedness, for interrogation by the British armed forces is desirable

PREDICTING THE OUTCOME OF RODENTICIDE TRIALS AGAINST NORWAY RATS LIVING ON FARMS

Difenacoum and bromadiolone treatments against Norway rats may fail because: 1) the animals eat little or no bait, 2) reinvasion rapidly offsets any success, or 3) the population contains resistant individuals. By monitoring bait takes and employing independent measures of rat activity such as tracking plates, it is possible to identify, often in the early stages of a treatment, patterns that indicate the contribution of each of these causes to the eventual outcome. If there is no bait take from the majority of bait points visited by rats in the first week then the treatment is unlikely to be successful, no matter how long it continues. Furthermore, treatments carried out on arable farms, where cereals are stored and the environment is relatively undisturbed, are likely to be less successful than those carried out on livestock farms, where alternative food may also be abundant but where the environment is less predictable. Bait takes that persist at the same bait points for longer than 16 days strongly suggest the presence of resistant rats, while immigration may be significantly affecting the treatment if takes recur at more than 30% of points after a period of seven days. Once a given problem has been identified remedial measures can be taken