The HartX period May 1992, seen against the background of twenty years of energy balance climatology at the Hartheim pine plantation

Summary The experimental site of the Department of Meteorology of Freiburg University at the Hartheim pine stand is first described. There, since 1973 long term measurements of net radiation and its components have been carried out. In addition we have been monitoring the different heat fluxes and components of the forest water budget.From May 11th to May 24th 1992 a special international and interdisciplinary observation period was organized in Hartheim (HartX 92). This took place in the frame of the international regional climatic project REKLIP (Regionales Klima Projekt). We then describe the permanent equipment and the special HartX installations. After that we show the climate of the region, in May 1992 and the weather during the HartX period. It was extraordinarily warm and the precipitation was much less than normal. The cloud cover was very small.We report the results of the radiation measurements (net radiation and its components). They are compared to the long standing measurements (1974–1988). Moreover the longstanding data of the components of the water budget (throughfall, canopy drip and stemflow, interception and transpiration) of the period 1978–1985 are dealt with. In addition we report the behaviour of the energy fluxes (soil-stand heat flux, turbulent sensible and latent heat fluxes) of the period 1974–1988. These estimations are compared to the conditions in May 1992 and the conditions during HartX 92.With 8 Figures     

Über eine Art von Pseudodolinen

Ohne Zusammenfassung     

Einige Wüstenerscheinungen aus nicht aridem Klima

Ohne Zusammenfassung     

Aligning tourist,industry and government expectations: A case study from the swim with whales industry in Tonga

Swimming with humpback whales in the Kingdom of Tonga is a growing industry that provides important revenue for a small Pacific Island economy. However the sustainability of this industry has been questioned due to its potential impact on the animals involved. The activity focuses on an ‘endangered’ subpopulation of humpback whales, with swimming occurring in the breeding area primarily with groups of animals containing young calves. This paper examines the relationship between the existing Tongan Government draft regulations and Tonga Whale Watching Operator Association guidelines that control the industry and visitor expectations about the management of the activity. There is significant support from visitors for strong, easy to understand and enforceable regulations governing the swim with whales industry. There is a clear correlation between current moves to strengthen Government regulations and the expectation from visitors that their activity is, and will be, conducted in a sustainable manner. The study recommends that to ensure compliance with regulations, appropriate management fees should be charged, visitors should be engaged in environmental education activities and further research should be conducted on the impacts of swimming with humpback whales.     

On condensation oscillations

Condensation oscillations in showers and thunderstorms are represented by variations in the vertical air currents that are induced by the accumulation and fallout of condensed water. A simple analytic theory of condensation oscillations and calculations on more complete numerical models indicate that their period is approximately proportional to the inverse square root of the condensation function, i.e. the amount of condensate produced per unit rise of saturated air, and that the period is independent of the magnitude of thermal buoyancy.     

Development and skill assessment of a real-time hydrologic-hydrodynamic-wave modeling system for Lake Champlain flood forecasting

Ocean Dynamics - In response to record-breaking flooding on Lake Champlain in 2011, the International Joint Commission launched a 5-year study to explore solutions to flooding in the binational...     

Correction to: Inertial instability and phase error in Euler forward predictorcorrector time integration schemes: Improvement of modeling Great Lakes thermal structure and circulation using FVCOM

This study investigates the inertial stability properties and phase error of numerical time integration schemes in several widely-used ocean and atmospheric models. These schemes include the most widely used centered differencing (i.e., leapfrog scheme or the 3-time step scheme at n-1, n, n+1) and 2-time step (n, n+1) 1^st-order Euler forward schemes, as well as 2^nd-stage and 3^rd- and 4^th-stage Euler predictor-corrector (PC) schemes. Previous work has proved that the leapfrog scheme is neutrally stable with respect to the Coriolis force, with perfect inertial motion preservation, an amplification factor (AF) equal to unity, and a minor overestimation of the phase speed. The 1^st-order Euler forward scheme, on the other hand, is known to be unconditionally inertially unstable since its AF is always greater than unity. In this study, it is shown that 3^rd- and 4^th-order predictor-corrector schemes 1) are inertially stable with weak damping if the Coriolis terms are equally split to n+1 (new value) and n (old value); and 2) introduce an artificial computational mode. The inevitable phase error associated with the Coriolis parameter is analyzed in depth for all numerical schemes. Some schemes (leapfrog and 2^nd-stage PC schemes) overestimate the phase speed, while the others (1^st-order Euler forward, 3^rd- and 4^th-stage PC schemes) underestimate it. To preserve phase speed as best as possible in a numerical model, alternating a scheme that overestimates the phase speed with a scheme that underestimates the phase speed is recommended. Considering all properties investigated, the leapfrog scheme is still highly recommended for a time integration scheme. As an example, a comparison between a leapfrog scheme and a 1^st-order Euler forward scheme is presented to show that the leapfrog scheme reproduces much better vertical thermal stratification and circulation in the weakly-stratified Great Lakes.

     

Effects of vertical mixing on the Lake Michigan food web: an application of a linked end-to-end earth system model framework

Ocean Dynamics - Physical processes may affect ecosystem structure and function through the accumulation, transport, and dispersal of organic and inorganic materials, nutrients, and organisms; they...