Modeling the Vegetation Atmospheric Exchange with a Transilient Model

2004 ◽  
pp. 177-190 ◽  
Author(s):  
M. Berger ◽  
R. Dlugi ◽  
T. Foken
Keyword(s):  
Atmospheric Exchange

scholarly journals Meteorological Applications Benefiting from an Improved Understanding of Atmospheric Exchange Processes over Mountains

Atmosphere ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 371 ◽  
Author(s):  
Stephan De Wekker ◽  
Meinolf Kossmann ◽  
Jason Knievel ◽  
Lorenzo Giovannini ◽  
Ethan Gutmann ◽  
...  
Keyword(s):  
Climate Change ◽  
Air Pollution ◽  
Basic Research ◽  
Future Research ◽  
Economic Sectors ◽  
Scientific Disciplines ◽  
Exchange Processes ◽  
Atmospheric Exchange ◽  
New Research ◽  
Energy Transportation

This paper reviews the benefits of a better understanding of atmospheric exchange processes over mountains. These processes affect weather and climate variables that are important in meteorological applications related to many scientific disciplines and sectors of the economy. We focus this review on examples of meteorological applications in hydrology, ecology, agriculture, urban planning, wind energy, transportation, air pollution, and climate change. These examples demonstrate the benefits of a more accurate knowledge of atmospheric exchange processes over mountains, including a better understanding of snow redistribution, microclimate, land-cover change, frost hazards, urban ventilation, wind gusts, road temperatures, air pollution, and the impacts of climate change. The examples show that continued research on atmospheric exchange processes over mountains is warranted, and that a recognition of the potential benefits can inspire new research directions. An awareness of the links between basic research topics and applications is important to the success and impact of new efforts that aim at better understanding atmospheric exchange processes over mountains. To maximize the benefits of future research for meteorological applications, coordinated international efforts involving scientists studying atmospheric exchange processes, as well as scientists and stakeholders representing many other scientific disciplines and economic sectors are required.

scholarly journals The importance of freshwater systems to the net exchange of atmospheric carbon dioxide and methane with rapidly changing high Arctic landscapes

2016 ◽  
Author(s):  
Craig A. Emmerton ◽  
Vincent L. St. Louis ◽  
Igor Lehnherr ◽  
Jennifer A. Graydon ◽  
Jane L. Kirk ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Carbon Dioxide ◽  
High Arctic ◽  
Atmospheric Co2 ◽  
Arctic Ecosystems ◽  
Freshwater Systems ◽  
Atmospheric Exchange ◽  
Net Uptake ◽  
Carbon Dioxide Co2 ◽  
Few Data

Abstract. A warming climate is rapidly changing the distribution and exchanges of carbon within high Arctic ecosystems. Few data exist, however, which quantify exchange of both carbon dioxide (CO2) and methane (CH4) between the atmosphere and freshwater systems, or estimate freshwater contributions to total catchment exchange of these gases, in the high Arctic. During the summers of 2005 and 2007–2012, we quantified CO2 and CH4 concentrations in, and atmospheric exchange with, common freshwater systems in the high Arctic watershed of Lake Hazen, Nunavut, Canada. We identified four types of biogeochemically-distinct freshwater systems in the watershed, however mean CO2 concentrations (21–28 μmol L−1) and atmospheric exchange (−0.013–0.046 g C-CO2 m−2 d−1) were similar between these systems. Seasonal flooding of ponds bordering Lake Hazen generated considerable CH4 emissions to the atmosphere (0.008 g C-CH4 m−2 d−1), while all other freshwater systems were minimal emitters of this gas (< 0.001 g C-CH4 m−2 d−1). Measurements made on terrestrial landscapes in the same watershed between 2008–2012 determined that the near-barren polar semidesert was a very weak consumer of atmospheric CO2 (−0.004 g C-CO2 m−2 d−1), but an important consumer of atmospheric CH4 (−0.001 g C-CH4 m−2 d−1). Alternatively, meadow wetlands were very productive consumers of atmospheric CO2 (−0.96 g C-CO2 m−2 d−1) but relatively weak emitters of CH4 to the atmosphere (0.001 g C-CH4m−2 d−1). When using ecosystem-cover classification mapping, we found that freshwaters were unimportant contributors to total watershed carbon exchange, in part because they covered less than 10 % of total cover in the watershed. High Arctic watersheds are experiencing warmer and wetter climates than in the past, which may have implications for the net uptake of carbon greenhouse gases by currently underproductive polar semidesert and freshwater systems.

scholarly journals The 2009–2010 step in atmospheric CO<sub>2</sub> inter-hemispheric difference

2015 ◽  
Vol 12 (17) ◽  
pp. 15087-15109 ◽  
Author(s):  
R. J. Francey ◽  
J. S. Frederiksen
Keyword(s):  
Atmospheric Transport ◽  
Anthropogenic Emissions ◽  
Hemispheric Difference ◽  
Critical Test ◽  
Transport Models ◽  
Annual Average ◽  
Mauna Loa ◽  
Atmospheric Exchange ◽  
Source Sink ◽  
Global Carbon

Abstract. The annual average CO2 difference between baseline data from Mauna Loa and the Southern Hemisphere increased by ∼ 0.8 μmol mol−1 (0.8 ppm) between 2009 and 2010, a step unprecedented in over 50 years of reliable data. We find no evidence for coinciding, sufficiently large and rapid, source/sink changes. A statistical anomaly is unlikely due to the highly systematic nature of the variation in observations. An explanation for the step, and the subsequent 5 year stability in this north–south difference, involves inter-hemispheric atmospheric exchange variation. The selected data describing this episode provide a critical test for studies that employ atmospheric transport models that interpret global carbon budgets and inform management of anthropogenic emissions.

SHORT COMMUNICATION: Exchange of 15N among plants in controlled environment studies

1994 ◽  
Vol 74 (1) ◽  
pp. 109-110 ◽  
Author(s):  
H. H. Janzen ◽  
C. Gilbertson
Keyword(s):  
Key Words ◽  
Nitrogen Fertilizer ◽  
Short Communication ◽  
Controlled Environment ◽  
Atmospheric Ammonia ◽  
Atmospheric Exchange ◽  
Selection Of ◽  
Air Exchange

Barley receiving unlabelled nitrogen fertilizer was grown among treatments receiving Ca(15NO3)2 fertilizer (5 atom %) in a growth cabinet with high air exchange and in a greenhouse. In both environments, the unlabelled plants and soil were significantly enriched with 15N, apparently, in part, by foliar exchange of atmospheric ammonia. This exchange may warrant consideration in the selection of appropriate controls for 15N calculations. Key words:15N, ammonia, atmospheric exchange

Tracer Studies of Atmospheric Exchange Based on Measurements of Cosmic Ray Produced Sodium-22

1968 ◽  
Vol 23 (1) ◽  
pp. 51-55 ◽  
Author(s):  
W. Roedel
Keyword(s):  
Cosmic Ray ◽  
Tracer Studies ◽  
Atmospheric Exchange

Die Ergebnisse der in Heidelberg während des Jahres 1966 durchgeführten Messungen des durch die kosmische Strahlung in der Atmosphäre erzeugten Na22 werden dargestellt. Anhand eines einfachen Modells wird versucht, von den ausschließlich am Boden gewonnenen Meßwerten auf den Austausch zwischen Stratosphäre und Troposphäre zu schließen. Die Modell-Rechnung liefert für das an Aerosole angelagerte Na22 eine mittlere Aufenthaltsdauer in der Stratosphäre von 12,3 Monaten; die durch die Tropopause ausgetauschten Luftmengen liegen nach dieser Rechnung zwischen Null (im Spätjahr) und 48 g/cm2 · Monat (im Frühjahr).Im Anhang wird die Abnahme des durch die Kernwaffentests von 1961 und 1962 künstlich produzierten Na22 diskutiert. Es wird gezeigt, daß die künstliche Aktivität in der Atmosphäre bis auf einen vernachlässigbaren Rest abgefallen ist.

Soil-atmospheric exchange of CO2 , CH4 , and N2 O in three subtropical forest ecosystems in southern China

2006 ◽  
Vol 12 (3) ◽  
pp. 546-560 ◽  
Author(s):  
XULI TANG ◽  
SHUGUANG LIU ◽  
GUOYI ZHOU ◽  
DEQIANG ZHANG ◽  
CUNYU ZHOU
Keyword(s):  
Forest Ecosystems ◽  
Southern China ◽  
Subtropical Forest ◽  
Atmospheric Exchange

Cultural conditions influencing Basidium formation in the Ceratobasidiaceae

1984 ◽  
Vol 32 (1) ◽  
pp. 101 ◽  
Author(s):  
DIL Murray
Keyword(s):  
Yeast Extract ◽  
External Environment ◽  
Petri Dish ◽  
Physical Characteristics ◽  
Sporulation Medium ◽  
Extract Agar ◽  
Cultural Conditions ◽  
Atmospheric Exchange ◽  
Primary Substrate ◽  
Yeast Extract Agar

Adequate aeration of cultures was shown to be essential for basidium formation in isolates of several species belonging in the Ceratobasidiaceae. Moreover, fruiting was strongly influenced by the physical characteristics of three commercially available brands of petri dish that differed in their capacity to permit atmospheric exchange between the interior of the dish and the external environment. Dextrose-yeast extract agar, on which fungi were grown before transferring to sporulation media, was found to be a suitable primary substrate for eight of 10 species tested but basidium formation in most isolates was critically affected by the composition of the sporulation medium and by the volume of incculum transferred. The significance of these findings is considered in relation to the potential of existing methods to give reproducible leve!s of basidium fcrmation in different laboratories.

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