• Title/Summary/Keyword: climate system

Search Result 2,577, Processing Time 0.027 seconds

Precipitation forecasting by fuzzy Theory : I - Applications of Neuro-fuzzy System and Markov Chain (퍼지론에 의한 강수예측 : I. 뉴로-퍼지 시스템과 마코프 연쇄의 적용)

  • Na, Chang-Jin;Kim, Hung-Soo;Kim, Joong-Hoon;Kang, In-Joo
    • Journal of Korea Water Resources Association
    • /
    • v.35 no.5
    • /
    • pp.619-629
    • /
    • 2002
  • Water in the atmosphere is circulated by reciprocal action of various factors in the climate system. Otherwise, any climate phenomenon could not occur of itself. Thus, we have tried to understand the climate change by analysis of the factors. In this study, the fuzzy theory which is useful to express inaccurate and approximate nature in the real world is used for forecasting precipitation influenced by the factors. Forecasting models used in this study are neuro-fuzzy system and a Markov chain and those are applied to precipitation forecasting of illinois. Various atmosphere circulation factors(like soil moisture and temperature) influencing the climate change are considered to forecast precipitation. As a forecasting result, it can be found that the considerations of the factors are helpful to increase the forecastibility of the models and the neuro-fuzzy system gives us relatively more accurate forecasts.

Evaluation of Reference Evapotranspiration in South Korea according to CMIP5 GCMs and Estimation Methods (CMIP5 GCMs과 추정 방법에 따른 우리나라 기준증발산량 평가)

  • Park, Jihoon;Cho, Jaepil;Lee, Eun-Jeong;Jung, Imgook
    • Journal of Korean Society of Rural Planning
    • /
    • v.23 no.4
    • /
    • pp.153-168
    • /
    • 2017
  • The main objective of this study was to assess reference evapotranspiration based on multiple GCMs (General Circulation Models) and estimation methods. In this study, 10 GCMs based on the RCP (Representative Concentration Pathway) 4.5 scenario were used to estimate reference evapotranspiration. 54 ASOS (Automated Synoptic Observing System) data were constructed by statistical downscaling techniques. The meteorological variables of precipitation, maximum temperature and minimum temperature, relative humidity, wind speed, and solar radiation were produced using GCMs. For the past and future periods, we estimated reference evapotranspiration by GCMs and analyzed the statistical characteristics and analyzed its uncertainty. Five methods (BC: Blaney-Criddle, HS: Hargreaves-Samani, MK: Makkink, MS: Matt-Shuttleworth, and PM: Penman-Monteith) were selected to analyze the uncertainty by reference evapotranspiration estimation methods. We compared the uncertainty of reference evapotranspiration method by the variable expansion and analyzed which variables greatly influence reference evapotranspiration estimation. The posterior probabilities of five methods were estimated as BC: 0.1792, HS: 0.1775, MK: 0.2361, MS: 0.2054, and PM: 0.2018. The posterior probability indicated how well reference evapotranspiration estimated with 10 GCMs for five methods reflected the estimated reference evapotranspiration using the observed data. Through this study, we analyzed the overall characteristics of reference evapotranspiration according to GCMs and reference evapotranspiration estimation methods The results of this study might be used as a basic data for preparing the standard method of reference evapotranspiration to derive the water management method under climate change.

Development of Spatial Statistical Downscaling Method for KMA-RCM by Using GIS (GIS를 활용한 KMA-RCM의 규모 상세화 기법 개발 및 검증)

  • Baek, Gyoung-Hye;Lee, Moun-Gjin;Kang, Byung-Jin
    • Journal of the Korean Association of Geographic Information Studies
    • /
    • v.14 no.3
    • /
    • pp.136-149
    • /
    • 2011
  • The aim of this study is to develop future climate scenario by downscaling the regional climate model (RCM) from global climate model (GCM) based on IPCC A1B scenario. To this end, the study first resampled the KMA-RCM(Korea meteorological administration-regional climate model) from spatial resolution of 27km to 1km. Second, observed climatic data of temperature and rainfall through 1971-2000 were processed to reflect the temperature lapse rate with respect to the altitude of each meteorological observation station. To optimize the downscaled results, Co-kriging was used to calculate temperature lapse-rate; and IDW was used to calculate rainfall lapse rate. Fourth, to verify results of the study we performed correlation analysis between future climate change projection data and observation data through the years 2001-2010. In this study the past climate data (1971-2000), future climate change scenarios(A1B), KMA-RCM(Korea meteorological administration-regional climate model) results and the 1km DEM were used. The research area is entire South Korea and the study period is from 1971 to 2100. Monthly mean temperatures and rainfall with spatial resolution of 1km * 1km were produced as a result of research. Annual average temperature and precipitation had increased by $1.39^{\circ}C$ and 271.23mm during 1971 to 2100. The development of downscaling method using GIS and verification with observed data could reduce the uncertainty of future climate change projection.

Estimation of Food Miles and CO2 Emissions of Imported Food (수입 음식료품의 푸드 마일리지 및 이산화탄소 배출량 산정)

  • Ju, Ok-Jung;Lee, Jae-Bum;Seong, Mi-Ae;Kim, Su-Yeon;Ryu, Ji-Yeon;Kim, Dai-Gon;Hong, Yoo-Deog
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.26 no.1
    • /
    • pp.57-68
    • /
    • 2010
  • Increase in greenhouse gas emissions during the last century has led to remarkable changes in our environment and climate system. Many policy measures have been developed to reduce greenhouse gas emissions across the world, many of which require our lifestyle changes from energy-intensive to energy-saving. One of the changes in our living patterns is to consider food miles. A food mile is the distance food travels from where it is produced to where it is consumed. Providing information of food miles will help people choose low mileage food, helping promote a "green consumption" action and lead to a low carbon society with emission reduction systems. In this study, 10 items are selected from 23 Harmonized commodity description and 2-digit coding system (HS) to estimate their food miles, and $CO_2$ emissions released in the transportation of imported food. For the estimation, four countries are chosen-Korea, Japan, United Kingdom (UK) and France, with Korea and Japan's 2001, 2003, and 2007 trade statistics and UK and France's 2003 and 2007 trade statistics used. As a result, Korea showed in 2007 the highest level of food miles and $CO_2$ emissions per capita among 4 countries. That suggests that Korea should make an effort to purchase local food to reduce food miles and use low-carbon vehicles for food transport, contributing to reducing greenhouse gas emissions.

Vulnerability Assessment of Human Health Sector due to Climate Change: Focus on Ozone (기후변화에 따른 보건 분야의 취약성 평가: O3을 중심으로)

  • Lee, Jae-Bum;Lee, Hyun-Ju;Moon, Kyung-Jung;Hong, Sung-Chul;Kim, Deok-Rae;Song, Chang-Keun;Hong, You-Deog
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.28 no.1
    • /
    • pp.22-38
    • /
    • 2012
  • Adaptation of climate change is necessary to avoid unexpected impacts of climate change caused by human activities. Vulnerability refers to the degree to which system cannot cope with impacts of climate change, encompassing physical, social and economic aspects. Therefore the quantification of climate change impacts and its vulnerability is needed to identify vulnerable regions and to setup the proper strategies for adaptation. In this study, climate change vulnerability is defined as a function of climate exposure, sensitivity, and adaptive capacity. Also, we identified regions vulnerable to ozone due to climate change in Korea using developed proxy variables of vulnerability of regional level. 18 proxy variables are selected through delphi survey to assess vulnerability over human health sector for ozone concentration change due to climate change. Also, we estimate the weighting score of proxy variables from delphi survey. The results showed that the local regions with higher vulnerability index in the sector of human health are Seoul and Daegu, whereas regions with lower one are Jeollanam-do, Gyeonggi-do, Gwangju, Busan, Daejeon, and Gangwon-do. The regions of high level vulnerability are mainly caused by their high ozone exposure. We also assessed future vulnerability according to the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A2, A1FI, A1T, A1B, B2, and B1 scenarios in 2020s, 2050s and 2100s. The results showed that vulnerability increased in all scenarios due to increased ozone concentrations. Especially vulnerability index is increased by approximately 2 times in A1FI scenarios in the 2020s. This study could support regionally adjusted adaptation polices and the quantitative background of policy priority as providing the information on the regional vulnerability of ozone due to climate change in Korea.

Analysis on the Effect of Local Climate on the Unit-type Ground Heat Exchanger (지역 기후가 유닛형 지중열교환기 성능에 미치는 영향)

  • Bae, Sangmu;Kim, Jae-Min;Nam, Yujin
    • Journal of the Korean Solar Energy Society
    • /
    • v.39 no.1
    • /
    • pp.67-76
    • /
    • 2019
  • A ground source heat pump (GSHP) system can stable system operation by using underground heat source and has high reliability for energy production. However, wide-spread of the GSHP system is delayed to high initial investment costs. In previous studies, horizontal and unit-type ground heat exchanger (GHX) have developed to overcome disadvantages such as high initial cost. However, these performances of GHXs are greatly influenced by climate and weather conditions. It is necessary to analyze the performance of GHX according to the ground temperature change in the installation site. In this study, the ground temperature of each installation site confirmed and performance of unit-type GHX quantitatively analyzed by numerical analysis. As the result, the performance of the unit type GHX was 33.9 W/m in Seoul, 34.2 W/m in Daejeon, and 37.2 W/m in Busan.The result showed the difference performance of GHX according to local climate was maximum of 9.7%.

Uncertainties estimation of AOGCM-based climate scenarios for impact assessment on water resources (수자원 영향평가를 위한 기후변화 시나리오의 불확실성 평가)

  • Park E-Hyung;Im Eun-Soon;Kwon Won-Tae;Lee Eun-Jeong
    • Proceedings of the Korea Water Resources Association Conference
    • /
    • 2005.05b
    • /
    • pp.138-142
    • /
    • 2005
  • The change of precipitation and temperature due to the global. warming eventually caused the variation of water availability in terms of potential evapotranspiration, soil moisture, and runoff. In this reason national long-term water resource planning should be considered the effect of climate change. Study of AOGCM-based scenario to proposed the plausible future states of the climate system has become increasingly important for hydrological impact assessment. Future climate changes over East Asia are projected from the coupled atmosphere-ocean general circulation model (AOGCM) simulations based on Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A2 and B2 scenarios using multi-model ensembles (MMEs) method (Min et al. 2004). MME method is used to reduce the uncertainty of individual models. However, the uncertainty increases are larger over the small area than the large area. It is demonstrated that the temperature increases is larger over continental area than oceanic area in the 21st century.

  • PDF

Vulnerability Assessment of Sub-Alpine Vegetations by Climate Change in Korea (한반도 지역의 기후변화에 의한 고산·아고산 식생 취약성 평가)

  • Lee, Dong-Kun;Kim, Jae-Uk
    • Journal of the Korean Society of Environmental Restoration Technology
    • /
    • v.10 no.6
    • /
    • pp.110-119
    • /
    • 2007
  • This study's objects are to predict distribution and to assess vulnerability of sub-alpine vegetations in the Korean peninsula for climate change using various climate models. This study validates relationship between sub-alpine vegetations and environmental factors using Pearson correlation analysis. Then, the future distribution of sub-alpine vegetations are predicted by a logistic regression. The major findings in this study are; First, spring mean temperature (March-May), total precipitation, elevation and warmth index are highly influencing factors to the distribution of sub-alpine vegetations. Second, the sub-alpine vegetations will be disappeared in South Korea and concentrated around Baekdu Mountain in North Korea. North Korea is predicted to have serious impact of climate change because temperature will be increased higher than in South Korea. The study findings concluded that the assessment of the future vulnerability of sub-alpine vegetations to climate change are significant.

Generating global warming scenarios with probability weighted resampling and its implication in precipitation with nonparametric weather generator

  • Lee, Taesam;Park, Taewoong
    • Proceedings of the Korea Water Resources Association Conference
    • /
    • 2015.05a
    • /
    • pp.226-226
    • /
    • 2015
  • The complex climate system regarding human actions is well represented through global climate models (GCMs). The output from GCMs provides useful information about the rate and magnitude of future climate change. Especially, the temperature variable is most reliable among other GCM outputs. However, hydrological variables (e.g. precipitation) from GCM outputs for future climate change contain too high uncertainty to use in practice. Therefore, we propose a method that simulates temperature variable with increasing in a certain level (e.g. 0.5oC or 1.0oC increase) as a global warming scenario from observed data. In addition, a hydrometeorological variable can be simulated employing block-wise sampling technique associated with the temperature simulation. The proposed method was tested for assessing the future change of the seasonal precipitation in South Korea under global warming scenario. The results illustrate that the proposed method is a good alternative to levy the variation of hydrological variables under global warming condition.

  • PDF