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Koopman et al. (2014) developed a method to consistently decompose gross exports in value-added terms that accommodate infinite repercussions of international and inter-sector transactions. This provides a better understanding of trade in value added in global value chains than does the conventional gross exports method, which is affected by double-counting problems. However, the new framework is based on monetary input--output (IO) tables and cannot distinguish prices from quantities; thus, it is unable to consider financial adjustments through the exchange market. In this paper, we propose a framework based on a physical IO system, characterized by its linear programming equivalent that can clarify the various complexities relevant to the existing indicators and is proved to be consistent with Koopman's results when the physical decompositions are evaluated in monetary terms. While international monetary tables are typically described in current U.S. dollars, the physical framework can elucidate the impact of price adjustments through the exchange market. An iterative procedure to calculate the exchange rates is proposed, and we also show that the physical framework is also convenient for considering indicators associated with greenhouse gas (GHG) emissions.

地球温暖化は人類の持続可能性を危うくする問題という認識が広がり，大循環モデル(GCM) を用いて長期的な気候変化に関する緻密な予測がなされている。しかしGCMの予測は，経済活動に関する固定的なシナリオに基づいており，排出権価格の上昇や災害の増加が経済活動へ及ぼす影響は考慮され得ない。本稿はGCMモデルと対話的に実行できる，リカーシブな経済活動モデルの提案を目的とする。モデルは準動学的なSCGE(空間応用一般均衡) モデルとして記述され，水災害の影響を考慮した財生産・CO2 排出量とそれらの価格が地域別に算出可能な枠組みを提供するが，技術的にはGCMとSCGE モデルの空間的・時間的解像度の相違に関するインターフェイスの提案がポイントとなる。, As global warming becomes the issue of human sustainability, the General Circulation Model (GCM) has been developed to forecast future climate change. While its results are based on fixed scenarios of economic activities, we propose a recursive dynamic model that can be operated interactively with a GCM. Then it is important to interface the spatial and time scales used in economic and circulation models. The former is formulated as a SCGE model that calculates quantities of goods and CO2 emission, which are priced through the market, considering impacts of floods and droughts caused by climate change.

This paper presents a framework for an SCGE model that is compatible with the Armington assumption and explicitly considers transport activities. In the model, the trade coefficient takes the form of a potential function,and the equilibrium market price becomes similar to the price index of varietal goods in the context of new economic geography (NEG). The features of the model are investigated by using the minimal setting, which comprises two non-transport sectors and three regions. Because transport costs are given exogenously to facilitate study of their impacts, commodity prices are also determined relative to them. The model can be described as a system of homogeneous equations, where an output in one region can arbitrarily be determined similarly as a price in the Walrasian equilibrium. The model closure is sensitive to formulation consistency so that homogeneity of the system would be lost by use of an alternative form of trade coefficients.

The Armington Assumption in the context of multi-regional CGE models is commonlyinterpreted as follows: Same commodities with different origins are imperfect substitutes for eachother. In this paper, a static spatial CGE model that is compatible with this assumption andexplicitly considers the transport sector and regional price differentials is formulated. Tradecoefficients, which are derived endogenously from the optimization behaviors of firms andhouseholds, are shown to take the form of a potential function. To investigate how the elasticityof substitutions affects equilibrium solutions, a simpler version of the model that incorporatesthree regions and two sectors (besides the transport sector) is introduced. Results indicate: (1) ifcommodities produced in different regions are perfect substitutes, regional economies will beeither autarkic or completely symmetric and (2) if they are imperfect substitutes, the impact ofelasticity on the price equilibrium system as well as trade coefficients will be nonlinear andsometimes very sensitive.

With regression formulas replaced by equilibrium conditions, a spatial CGE model can substantially reduce data requirements. Detailed regional analyses are thus possible in countries where only limited regional statistics are available. While regional price differentials play important roles in multi-regional settings, transport does not receive much attention in existing models. This paper formulates a spatial CGE model that explicitly considers the transport sector and FOB/CIF prices. After describing the model, performance of our model is evaluated by comparing the benchmark equilibrium for China with survey-based regional I-O and interregional I-O tables for 1987. The structure of Chinese economies is summarized using information obtained from the benchmark equilibrium computation. This includes regional and sectoral production distributions and price differentials. The equilibrium for 1997 facilitates discussion of changes in regional economic structures that China has experienced in the decade.

The gravity model, entropy model, potential type model and others like these have been adopted to formulate interregional trade coefficients under the framework of Multi-Regional I-O (MRIO) analysis. Since most of these models are based upon analogies in physics or on statistical principles, they do not provide a theoretical explanation from the view of a firm's or individual's rational and deterministic decision making. In this paper, according to the deterministic choice theory, not only is an alternative formulation of the trade coefficients presented, but also a discussion of an appropriate definition for purchasing prices indices. Since this formulation is consistent with the MRIO system, it can be employed as a useful model-building tool in multi-regional models such as the spatial CGE model.

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