GC21B-01 INVITED
Simulation of Forest Cover Dynamics for Eastern Eurasian Boreal Forests view a pdf version of the talk
We are developing and testing a boreal zone forest dynamics model capable of simulating the forest cover dynamics of the Eurasian boreal forest, a major biospheric ecosystem with potentially large roles in the planetary carbon cycle and in the feedback between terrestrial surface and the atmosphere. In appreciating the role of this region in the coupling between atmosphere and terrestrial surface, on must understand the interactions between CO2 source/sink relationships (associated with growing or clearing forests) and the albedo effects (from changes in terrestrial surface cover). There is some evidence that in the Eurasian Boreal zone, the Carbon budget effects from forest change may oppose the albedo changes. This creates complex feedbacks between surface and atmosphere and motivates the need for a forest dynamics model that simultaneous represents forest vegetation and carbon storage and release. A forest dynamics model applied to Eastern Eurasia, FAREAST, has been tested using three types of information: 1. Direct species composition comparisons between simulated and observed mature forests at the same locations; 2. Forest type comparisons between simulated and observed forests along altitudinal gradients of several different mountains; 3. Comparison with forest stands in different succession stages of simulated forests. Model comparisons with independent data indicate the FAREAST model is capable of representing many of the broad features of the forests of Northeastern China. After model validation in the Northeast China region, model applications were developed for the forests of the Russian Far East. Continental-scale forest cover can be simulated to a relatively realistic degree using a forest gap model with standard representations of individual- plant processes. It appears that such a model, validated relatively locally in this case, in Northeastern China, can then be applied over a much larger region and under conditions of climatic change.
GC21B-02 INVITED
Top-down approach to West Siberian regional carbon budget: combination of the CO2 observations and inverse modeling view a pdf version of the talk
Joint Japanese-Russian project is aiming at top-down approach to West Siberian regional carbon budget estimation. Study is combining three main components: regional atmospheric CO2 observing network, regional carbon inventory (bottom-up approach), and inverse model of atmospheric CO2 surface emissions, sinks and transport, that links together CO2 observations and carbon inventories. Airborne air sampling programs and observations are conducted over Siberia since 1993, now at 4 sites. A tower network has been established in West Siberia since 2002 with total of planned 10 tower sites, 6 of them operating in 2005. Bottom-up inventory of the regional carbon pools is based on analysis of the forest/wetland biomass inventories and interannual changes in forest survey totals on eco-region levels. To support the forward and inverse model simulations, detailed soil and vegetation type maps, soil profile and vegetation structure databases were developed. The inverse model of the surface CO2 sources and sinks was used for observation network design and is applied now to the first complete set observational data for year 2005. Preliminary analysis of the multiyear Siberian CO2 observations with inverse model suggest that more carbon sink is needed in Siberia to match the atmospheric data than implied without the regional observations.
GC21B-03
Simulation of irrigation effect on water cycle in Yellow River catchment, China
The Yellow River is 5,464 km long with a catchment area of 794,712 km2 if the Erdos inner flow area is included. This river catchment is divided between the upper region (length: 3472 km, area: 428,235 km2) from the headwater to Lanzhou in Gansu province, the middle region (length: 1,206 km, area: 343,751 km2) from Lanzhou to Huayuankou in Henan province, and the lower region (length: 786 km, area: 22,726 km2) from Huayuankou to the estuary. This river is well known for high sand content, frequent floods, unique channel characteristics in the lower reach (the river bed is higher than the land outside the banks), and the limited water resources. Since the competition of a large-scale irrigation project in 1969, noticeable river drying has been observed in the Yellow River. This flow dry-up phenomena, i.e., zero-flow in sections of the river channel, resulting from the intense competition between water supply and water demand, has occurred more and more often during the last 30 years. It is very important for decision making to ensure sustainable water resource utilization whether human activities were the only cause of the water shortage, the climate has changed during the last several decades in this catchment, and the water shortage has anything to do with climatic warming. The present research focuses on simulating the groundwater/river irrigation-effects on the water/heat dynamics in the Yellow River catchment. We combined the NIES Integrated Catchment-based Eco-hydrology (NICE) model (Nakayama and Watanabe, 2004, 2006; Nakayama et al., 2006) with the agricultural model in order to evaluate river drying in the Yellow River (NICE-DRY). We simulated the water/heat dynamics in the entire catchment with a resolution of 10 km mesh by using the NICE-DRY. The model reproduced excellently the river discharge, soil moisture, evapotranspiration, groundwater level, crop water use, crop productivity, et al. Furthermore, we evaluated the role of irrigation on the water/heat budgets, and simulated the change of water/heat dynamics by human activity in order to help decision-making on sustainable development in the catchment.
GC21B-04 INVITED
Monitoring and Modeling of the Northern Eurasia Permafrost Dynamics view a pdf version of the talk (11.5 Mb!)
Permafrost has received much attention recently because surface temperatures are rising in most permafrost areas of the earth, bringing permafrost to the edge of widespread thawing and degradation. The thawing of permafrost that already occurs at the southern limits of the permafrost zone can generate dramatic changes in ecosystems and in infrastructure performance. As a part of IPY-related activities, we are starting a three-year project in Northern Eurasia sponsored by NASA. This project will be primarily focused on addressing the climate and hydrological aspects of the NEESPI program (Northern Eurasia Earth Science Partnership Initiative). It also reflects very well the goals of the Study of Environmental Arctic Change (SEARCH) program in detecting and elucidating the recent changes in the Arctic and their impacts on human lives and activities here. Observational data will be used in conjunction with a two-tiered modeling approach to simulate present, past and future permafrost conditions in the Northern Eurasia permafrost region. The observational data will consist of subsurface and surface data, together with relevant atmospheric and remote sensing data, for the entire Northern Eurasia permafrost domain. A significant portion of the permafrost data will be obtained within a framework of the IPY-core Thermal State of Permafrost (TSP) project. These data will be incorporated into a Geographical Information System (GIS) for spatially distributed permafrost models and for interpretation, synthesis and integration of observational and modeled results. Two tiers of model simulations will include (1) simulations for specific sites with maximum available information for calibration and validation, (2) spatially distributed simulations for the entire Northern Eurasia permafrost region using the improved GIPL model developed at the Permafrost Lab, University of Alaska Fairbanks. Simulations will be both retrospective (spanning the 20th century) and prognostic (spanning the 21st century). Synthesis and integration activities will be achieved through the utilization of soil and atmospheric data from a wide range of sources (including IPY/TSP project) in Northern Eurasia and by comparisons of present (measured) and simulated characteristics of the active layer and permafrost dynamics within the Northern Eurasia permafrost region. Mapping of the areas of potential permafrost degradation will be possible from the simulations for the Northern Eurasia permafrost domain.
GC21B-05 INVITED
Impact of Atmospheric Mineral Dust on the Surface Energy Balance and PAR in the NEESPI Study Domain
Large uncertainties in the effects of changing atmospheric aerosols are among the major factors currently limiting our understanding of and ability to predict global climate changes. The Northern Eurasia Earth Science Partnership Initiative (NEESPI) Science Plan identifies atmospheric aerosols and pollutions and their impacts on and interactions with the Earth systems (and terrestrial ecosystem dynamics in particular) as a cross-cutting topic of special interest. Wind-blown mineral dust, being an important atmospheric constituent in the NEESPI drylands, can exert a strong radiative impact as well as trigger a multitude of complex feedbacks that remain poorly defined. Given the intimate coupling between the land processes and wind-blown atmospheric dust and their importance in the climate system, an improved understanding of how land-use/land-cover changes affect Asian dust and associated feedbacks is urgently needed to make assessments of climate change more realistic. The focus of this talk will be on the impact of atmospheric dust on the surface energy balance and photosynthetically active radiation (PAR). Both processes play a key role in the ecosystem functioning as well as overall land-atmosphere interactions, but they are rarely considered in an integrated fashion. Focusing on Central and East Asia, we present the results of extensive radiative transfer modeling in the presence of dust over the different type of land surfaces. The surface albedo and land emissivity retrieved from MODIS and ASTER, respectively, were included in the modeling. The modifications of the radiative fields are quantified and used to estimate changes of surface temperatures, surface fluxes of heat and moisture, boundary layer height, surface winds and other dust induced changes. Formulation of the possible feedbacks in the coupled land-atmospheric dust system and implications for the integrated systems modeling will be addressed.
GC21B-06
Integrated Regional Assessment of Climate Change for Korean River Basins view a pdf version of the talk
As the first national assessment, we investigated the potential impacts of climate change on water resources in the Korean peninsula that has varying climates and complex topography. Together with the precipitation runoff modeling system model, we used high resolution climate change scenarios and population and industrial growth scenarios for 2030. Climate change alone is projected to decrease mean annual runoff by 10% in four major river basins located in southern Korea. Summer floods and spring droughts are likely to occur more frequently at the sub-basin scale, suggesting the increasing vulnerability of regional water resources to climate change. When climate change scenarios are combined with population and industrial growth scenarios, the geographical variations of water stress increased. This necessitates the need for water allocation among different water users under the changing environment. A tool is being developed to address optimizing water allocation under changes in water availability for a selected basin of Korea.