Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2011
Abstract
For tracer studies at the catchment scale, travel times are often assumed to be stationary. We question the validity of this assumption. We analyzed a series of tracer experiments conducted under exceptionally controlled conditions at Gårdsjön, Sweden. The Gårdsjön G1 catchment was covered by a roof underneath which natural throughfall has been replaced by artificial irrigation with a pre-defined chemical composition. This unique setup was used to perform replicated catchment scale Br tracer experiments under steady state storm flow conditions in five different years. A log-normal distribution function was fitted to all Br breakthrough curves. Fitted parameter values differed significantly for some of the experiments. These differences were not only related to the slightly different hydrologic boundary and initial conditions for the experiments, but also to seasonal changes in catchment properties that may explain the different flow paths during the experiments. We conclude that the travel time distribution is not only linked to discharge but also explicitly related to other water fluxes such as evapotranspiration, and that it is not stationary even under steady-state flow conditions. Since the attenuation of soluble pollutants is fundamentally linked to the travel times of water through the subsurface of a catchment, it is of crucial importance to understand the latter in detail. However, it is still unclear which are the dominant processes controlling their distribution.
Authors
Markus Reichstein Miguel D. Mahecha Nuño Carvalhais Gitta Lasslop Sonia I. Seneviratne Holger Lange Alessandro Cescatti Mirco MigliavaccaAbstract
The release of carbon dioxide (CO2) from the land surface via different respiratory processes is a major flux in the global carbon cycle, antipodal to CO2 uptake via photosynthesis. Understanding the sensitivity of respiratory processes to temperature is central for quantifying the climate–carbon cycle feedback. In a recent study we approximated the sensitivity of terrestrial ecosystem respiration to air temperature (Q10) across 60 FLUXNET sites. For this objective, we developed a novel methodology that circumvents seasonally confounding effects. Contrary to previous findings, our results suggest that Q10 is independent of mean annual temperature, does not differ among biomes, and is confined to values around 1.4 ± 0.1. However, the shape of the strong relation between photosynthesis and respiration is highly variable among sites. The results may partly explain a less pronounced climate–carbon cycle feedback than suggested by current carbon cycle climate models. In the talk we put our findings into context with other recent results and critically discuss their potential for evaluating temperature sensitivity of respiration in terrestrial biosphere models and parameterizing future land surface schemes.
Abstract
No abstract has been registered
Abstract
The collapse of the Soviet Union in the Central Asian countries has led to enormous challenges for them in ensuring a sustainable environment. Weak economies and lack of expertise in environmental sciences were important reasons for the Norwegian support to the environmental sector in this region. The State Forest Service of the Kyrgyz Republic and the Norwegian Forestry Group initiated the TEMP project, later renamed TEMP-CA, in the Kyrgyz Republic in 2004. Activities in the Republic of Tajikistan were included in 2007 and in the Republic of Uzbekistan from 2008. The forestry sectors in the Kyrgyz Republic and neighbouring countries in Central Asia, surrounding the Fergana Valley, are closely linked to the environmental and emergency planning sectors. Overgrazing and overharvesting have contributed to a dramatic decline in forest cover. The TEMP-CA project contributes to a better understanding of environmental problems and sustainable forestry in Central Asia. The TEMP-CA project has promoted institutional co-operation between Norway and the Central Asian countries as well as between different institutions both within and between the countries of Central Asia. Increased expertise for scientists, fieldworkers, laboratory staff and staff in different forest departments as well as institutional development in general are important outputs from the TEMP-CA project. The Umalak monitoring site in Tashkent region, the Republic of Uzbekistan, was the tenth of ten monitoring sites established in forests in Central Asia: 1: ”Kara-Koi” in the Osch oblast, the Kyrgyz Republic. 2: ”Sogot in the Jalal-Abad oblast, the Kyrgyz Republic. 3: “Dugoba” in Batken oblast, the Kyrgyz Republic. 4: “Besh-Tash” Talas oblast, the Kyrgyz Republic. 5: “Sary-Chelek”, in Jalal-Abad oblast, the Kyrgyz Republic. 6: “Navobod” in Sogdi oblast, the Republic of Tajikistan. 7: “Gauyan” in Batken oblast, the Kyrgyz Republic. 8: “Zaamin” in Djizak region, the Republic of Uzbekistan. 9: “Urumbash” in Jalal-Abad oblast, the Kyrgyz Republic. 10: “Umalak Teppa”, Tashkent region, the Republic of Uzbekistan. […]
Abstract
The collapse of the Soviet Union in the Central Asian countries has led to enormous challenges for them in ensuring a sustainable environment. Weak economies and lack of expertise in environmental sciences were important reasons for the Norwegian support to the environmental sector in this region. The State Forest Service of the Kyrgyz Republic and the Norwegian Forestry Group initiated the TEMP project, later renamed TEMP-CA, in the Kyrgyz Republic in 2004. Activities in the Republic of Tajikistan were included in 2007 and in the Republic of Uzbekistan from 2008. The forestry sectors in the Kyrgyz Republic and neighbouring countries in Central Asia, surrounding the Fergana Valley, are closely linked to the environmental and emergency planning sectors. Overgrazing and overharvesting have contributed to a dramatic decline in forest cover. The TEMP-CA project contributes to a better understanding of environmental problems and sustainable forestry in Central Asia. The TEMP-CA project has promoted institutional co-operation between Norway and the Central Asian countries as well as between different institutions both within and between the countries of Central Asia. Increased expertise for scientists, fieldworkers, laboratory staff and staff in different forest departments as well as institutional development in general are important outputs from the TEMP-CA project. […]
Abstract
The collapse of the Soviet Union in the Central Asian countries has led to enormous challenges for them in ensuring a sustainable environment. Weak economies and lack of expertise in environmental sciences were important reasons for the Norwegian support to the environmental sector in this region. The State Forest Service of the Kyrgyz Republic and the Norwegian Forestry Group initiated the TEMP project, later renamed TEMP-CA, in the Kyrgyz Republic in 2004. Activities in the Republic of Tajikistan were included in 2007 and in the Republic of Uzbekistan from 2008. The forestry sectors in the Kyrgyz Republic and neighbouring countries in Central Asia, surrounding the Fergana Valley, are closely linked to the environmental and emergency planning sectors. Overgrazing and overharvesting have contributed to a dramatic decline in forest cover. The TEMP-CA project contributes to a better understanding of environmental problems and sustainable forestry in Central Asia.The TEMP-CA project has promoted institutional co-operation between Norway and the Central Asian countries as well as between different institutions both within and between the countries of Central Asia. Increased expertise for scientists, fieldworkers, laboratory staff and staff in different forest departments as well as institutional development in general are important outputs from the TEMP-CA project.
Abstract
The collapse of the Soviet Union in the Central Asian countries has led to enormous challenges for them in ensuring a sustainable environment. Weak economies and lack of expertise in environmental sciences were important reasons for the Norwegian support to the environmental sector in this region. The State Forest Service of the Kyrgyz Republic and the Norwegian Forestry Group initiated the TEMP project, later renamed TEMP-CA, in the Kyrgyz Republic in 2004. Activities in the Republic of Tajikistan were included in 2007 and in the Republic of Uzbekistan from 2008. The forestry sectors in the Republic of Tajikistan and neighbouring countries in Central Asia, surrounding the Fergana Valley, are closely linked to the environmental and emergency planning sectors. Overgrazing and overharvesting have contributed to a dramatic decline in forest cover. The TEMP-CA project contributes to a better understanding of environmental problems and sustainable forestry in Central Asia. The TEMP-CA project has promoted institutional co-operation between Norway and the Central Asian countries as well as between different institutions both within and between the countries of Central Asia. Increased expertise for scientists, fieldworkers, laboratory staff and staff in different forest departments as well as institutional development in general are important outputs from the TEMP-CA project.
Abstract
The collapse of the Soviet Union in the Central Asian countries has led to enormous challenges for them in ensuring a sustainable environment. Weak economies and lack of expertise in environmental sciences were important reasons for the Norwegian support to the environmental sector in this region. The State Forest Service of the Kyrgyz Republic and the Norwegian Forestry Group initiated the TEMP project, later renamed TEMP-CA, in the Kyrgyz Republic in 2004. Activities in the Republic of Tajikistan were included in 2007 and in the Republic of Uzbekistan from 2008. The forestry sectors in the Kyrgyz Republic and neighbouring countries in Central Asia, surrounding the Fergana Valley, are closely linked to the environmental and emergency planning sectors. Overgrazing and overharvesting have contributed to a dramatic decline in forest cover. The TEMP-CA project contributes to a better understanding of environmental problems and sustainable forestry in Central Asia. The TEMP-CA project has promoted institutional co-operation between Norway and the Central Asian countries as well as between different institutions both within and between the countries of Central Asia. Increased expertise for scientists, fieldworkers, laboratory staff and staff in different forest departments as well as institutional development in general are important outputs from the TEMP-CA project. The Gauyan monitoring site in Batken oblast in the Kyrgyz Republic was the seventh of ten monitoring sites established in forests in Central Asia: 1: ”Kara-Koi” in the Osch oblast, the Kyrgyz Republic. 2: ”Sogot in the Jalal-Abad oblast, the Kyrgyz Republic. 3: “Dugoba” in Batken oblast, the Kyrgyz Republic. 4: “Besh-Tash” Talas oblast, the Kyrgyz Republic. 5: “Sary-Chelek”, in Jalal-Abad oblast, the Kyrgyz Republic. 6: “Navobod” in Sogdi oblast, the Republic of Tajikistan. 7: “Gauyan” in Batken oblast, the Kyrgyz Republic. 8: “Zaamin” in Djizak region, the Republic of Uzbekistan. 9: “Urumbash” in Jalal-Abad oblast, the Kyrgyz Republic. 10: “Umalak Teppa”, Tashkent region, the Republic of Uzbekistan.
Abstract
The collapse of the Soviet Union in the Central Asian countries has led to enormous challenges for them in ensuring a sustainable environment. Weak economies and lack of expertise in environmental sciences were important reasons for the Norwegian support to the environmental sector in this region. The State Forest Service of the Kyrgyz Republic and the Norwegian Forestry Group initiated the TEMP project, later renamed TEMP-CA, in the Kyrgyz Republic in 2004. Activities in the Republic of Tajikistan were included in 2007 and in the Republic of Uzbekistan from 2008. The forestry sectors in the Kyrgyz Republic and neighbouring countries in Central Asia, surrounding the Fergana Valley, are closely linked to the environmental and emergency planning sectors. Overgrazing and overharvesting have contributed to a dramatic decline in forest cover. The TEMP-CA project contributes to a better understanding of environmental problems and sustainable forestry in Central Asia. The TEMP-CA project has promoted institutional co-operation between Norway and the Central Asian countries as well as between different institutions both within and between the countries of Central Asia. Increased expertise for scientists, fieldworkers, laboratory staff and staff in different forest departments as well as institutional development in general are important outputs from the TEMP-CA project. [...]
Authors
Miguel D. Mahecha Markus Reichstein Nuño Carvalhais Gitta Lasslop Holger Lange Sonia I. Seneviratne Rodrigo Vargas Christof Ammann M. Altaf Arain Alessandro Cescatti Ivan A. Janssens Mirco Migliavacca Leonardo Montagnani Andrew D. RichardsonAbstract
We estimated the sensitivity of terrestrial ecosystem respiration to air temperature across 60 FLUXNET sites by minimizing the effect of seasonally confounding factors. Graf et al. now offer a theoretical perspective for an extension of our methodology. However, their critique does not change our main findings and, given the currently available observational techniques, may even impede a comparison across ecosystems.