과수지역 토양수분 시공간 분포 예측 및 적정 관개수량 산정기술개발

신승훈,박근형,김희태,김민영,이상봉,최용훈,김종건 강원대학교 농업생명과학연구원 2023 강원 농업생명환경연구 Vol.35 No.1

Moisture stress in the soil is one of the most important factors influencing plant growth. Soil moisture stress refers to a physiological response from excess moisture, such as the loss of more moisture than the moisture absorbed from the soil due to transpiration. Excessive soil moisture also causes considerable stress due to lack of air in the soil. To prevent moisture stress in the soil, it is important to estimate the appropriate amount of irrigation through spatial distribution prediction of soil moisture. At present, irrigation technology for field crop cultivation is being developed based on soil moisture and meteorological information (crop evapotranspiration). Therefore, in this study, we developed spatiotemporal distribution prediction technology by using soil moisture modeling techniques. We also developed a technique for estimating water stress and irrigation amount in open field crop areas by simulating soil moisture in the root zone. For the study area, an orchard located in Saam-ri, Chuncheon-si, Gangwon-do was selected. Soil moisture monitoring was performed according to the spatial distribution of soil moisture and soil depth. The soil moisture data was used as data for estimating and verifying the moisture simulation parameters of the APEX model and for comparing the predictions of root zone soil moisture at the monitoring site. As a result of this study, the spatial area vulnerable to drought within the study area was estimated, and the appropriate amount of irrigation was estimated accordingly. In line with the findings of this study, the spatial distribution of moisture can be predicted using a soil moisture simulation model.

실내 수증기 발생량 예측을 위한 습기 전달 모델의 검증에 관한 연구

이동권(Lee Dong-Kweon),김의종(Kim Eui-Jong),최원기(Choi Won-Ki),서승직(Suh Seung-Jik) 한국태양에너지학회 2006 한국태양에너지학회 논문집 Vol.26 No.1

Moisture in a building is one of the most important variables influencing building performance, human health, and comfort of indoor environment. However, there are still lacks in the knowledge of understanding the moisture problem well and controlling moisture. Accordingly, in order to provide the fundamental data to control moisture contents in the indoor air, this study was to predict moisture contents transferred through building envelopes and indoor moisture generation rate. Moisture transfer model was made by physical relations in each node, and the indoor moisture generation rate was gained by comparing the model with experimental analyses. From the study, we found out that moisture generation rate was critical and day-periodic, so that we predicted the indoor moisture content by substituting the constant value gained from the average in a day for the moisture generation rate.

Pattern similarity based soil moisture analysis for three seasons on a steep hillslope

Lee, Eunhyung,Kim, Sanghyun Elsevier 2017 Journal of hydrology Vol.551 No.-

<P><B>Abstract</B></P> <P>Soil moisture is an important factor for understanding hydrological and solute transport processes at the hillslope scale. The selection of representative points for soil moisture measurement has been explored to investigate temporal variation of average soil moisture with minimum costs and maximum stability. The optimal selection of soil moisture monitoring points has been reevaluated to address hillslope hydrological processes and the impacts of seasonal differences. An alternative method to select soil moisture measurement points was developed to adequately represent immediate soil moisture response patterns to sequential rainfall events. To address the seasonal features of rainfall events and their impacts on soil moisture redistribution along the hillslope, field soil moisture data were collected at 49 points for three seasons over periods of 25days with bi-hourly monitoring intervals. For effective characterization of soil moisture variation, soil moisture datasets were classified using cluster analysis based on Euclidean similarity. Points delineated using the proposed method not only provide better stability of average soil moistures but also adequately represent the response patterns of soil moisture to rainfall events on the hillslope.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We propose a new method for soil moisture monitoring points. </LI> <LI> The Euclidean similarity between datasets was used to characterize soil moisture. </LI> <LI> The method developed provides a better explanation for soil moisture patterns. </LI> </UL> </P>

Sentinel-1A/B SAR와 토양수분자료동화기법을 이용한 고해상도 토양수분 산정

김상우,이태화,천범석,정영훈,장원석,서찬양,신용철 한국농공학회 2020 한국농공학회논문집 Vol.62 No.6

We estimated the spatio-temporally distributed soil moisture using Sentinel-1A/B SAR (Synthetic Aperture Radar) sensor images and soil moisture dataassimilation technique in South Korea. Soil moisture data assimilation technique can extract the hydraulic parameters of soils using observed soilmoisture and GA (Genetic Algorithm). The SWAP (Soil Water Atmosphere Plant) model associated with a soil moisture assimilation technique simulatesthe soil moisture using the soil hydraulic parameters and meteorological data as input data. The soil moisture based on Sentinel-1A/B was validatedand evaluated using the pearson correlation and RMSE (Root Mean Square Error) analysis between estimated soil moisture and TDR soil moisture. The soil moisture data assimilation technique derived the soil hydraulic parameters using Sentinel-1A/B based soil moisture images, ASOS (AutomatedSynoptic Observing System) weather data and TRMM (Tropical Rainfall Measuring Mission)/GPM (Global Precipitation Measurement) rainfall data. Thederived soil hydrological parameters as the input data to SWAP were used to simulate the daily soil moisture values at the spatial domain from 2001to 2018 using the TRMM/GPM satellite rainfall data. Overall, the simulated soil moisture estimates matched well with the TDR measurements andSentinel-1A/B based soil moisture under various land surface conditions (bare soil, crop, forest, and urban).

콩의 생육시기에 따른 토양별 지중관수 공급량의 설계

김진현,김태욱,김설하,이황규,엄덕호,이상훈 경상대학교 농업생명과학연구원 2022 농업생명과학연구 Vol.56 No.5

지중점적 관수(subsurface drip irrigation, SDI)는 작물의 뿌리가 수분을 가장 쉽고 효과적으로 이용할 수 있는 방법으로 알려져 있다. 그러나 지중관수는 지표면 관수와 달리 수분의 공급 상태를 육안으로 확인하기 어려운 단점이 있다. 특히 작물의 뿌리가 수분을 흡수할 수 있는 유효수분 량은 토양에 따라 달라지고 동시에 수분을 보유하는 장력(potential energy)에도 영향을 미치게 된다. 지중관수는 지중에서 수분이 확산되는 위치 와 뿌리의 위치까지 도달될 때 효과가 발생한다. 그러나 실제로 토양 내부에서 수분이 이동하고 확산하는 것을 예측하기는 쉽지 않다. 따라서 본 연구에서는 토양의 조건을 일정하게 하고 토층을 파괴시키지 않기 위해 토양조를 이용하였다. 그리고 수분을 지중에 공급한 이후에 토양을 절개하고 토양의 내부 위치별 토양수분을 측정하였다. 이때 토양 내부의 수분함량이 동일한 분포선을 찾아 유효 수분영역을 구하고 공급한 지중관 수량과 비교하였다. 아울러 토양내부의 습윤 확산 형태와 수분량으로 부터 토성에 따른 수분 확산이론을 예측하였다. 여기서 얻어진 수분확산 예측선도와 콩의 생육 시기별 뿌리의 생장위치를 중첩하여 최종적으로 지중관수량을 구하였다. 콩의 뿌리 생육은 파종이후 일일 평균 10 mm 성장한 것으로 나타나 생육 초기에 10일 간격으로 지중관수 공급량을 설계하였다. 주요 결과는 미사질양토에서 유효수분량을 25-35%로 유지하기 위해, 생육초기인 파종후 10일에는 8000 mL, 파종후 20일에는 7000 mL, 파종후 30일에는 6500 mL를 공급해야 할 것으로 판단되었다. 사질토 에서는 유효수분량을 20-30%로 유지하려면 파종후 10일에는 7500 mL, 파종후 20일에는 6500 mL, 파종후 30일에는 6000 mL를 공급하는 것이 타당한 것으로 판단되었다. 또한 생육 30일 이후에는 미사질양토나 사질토 모두 6000 mL를 공급하는 것이 적절할 것으로 보여 진다. Subsurface drip irrigation (SDI) is known as the easiest and most effective method for the roots of crops to use moisture. However, unlike surface irrigation, subsurface drip irrigation has a disadvantage that it is difficult to visually check the supply state of moisture. In particular, the effective amount of moisture that the root of the crop can absorb moisture varies depending on the soil, and at the same time, it affects the tension that holds moisture. Subsurface drip irrigation occurs when it reaches the location of moisture diffusion and the location of the root. However, it is not easy to predict the movement and diffusion of moisture inside the soil. Therefore, in this study, soil tides were used to keep the conditions of the soil constant and not destroy the soil layer. In addition, after moisture was supplied to the ground, the soil was incised and soil moisture by internal location of the soil was measured. At this time, the distribution line with the same moisture content inside the soil was found to obtain an effective moisture area and compared with the supplied subsurface drip irrigation water supply. In addition, the theory of moisture diffusion according to saturn was predicted from the wet diffusion form and moisture content inside the soil. The water diffusion prediction line obtained here and the growth position of the roots by the growth period of soybeans were overlapped to finally obtain the subsurface drip irrigation water supply. The root growth of soybeans was found to have grown by an average of 10 mm per day after sowing, so the supply of subsurface drip irrigation water was designed at intervals of 10 days in the early stages of growth. The main result was that in order to maintain the effective moisture content at 25-35%, 8,000 mL should be supplied on the 10th day after sowing, 7,000 mL on the 20th day after sowing, and 6500 mL on the 30th day after sowing. In sandy soil, it was considered reasonable to supply 7500 mL on the 10th day after sowing, 6500 mL on the 20th day after sowing, and 6000 mL on the 30th day after sowing to maintain the effective moisture content at 20-30%. In addition, it would be appropriate to supply 6,000 mL of both silt soil and sandy soil after 30 days of growth.

VIC 모형을 이용하여 모의된 한반도 토양수분 자료의 분석 및 검증

조은샘,송성욱,유철상 한국습지학회 2017 한국습지학회지 Vol.19 No.1

본 연구에서는 지표수문해석모형을 이용하여 과거 30년에 대한 남한과 북한의 토양수분을 모의하고 그 거동 차이를 분석하였다. 아울러 VIC 모형의 모의결과를 평가하기 위해 Soil Moisture CCI에서 제공하는 위성관측 토양수분 자료 를 분석하였다. 모의결과와 관측자료 사이의 비교에는 CSEOF 분석을 적용하여 단순한 토양수분 값의 비교가 아닌 VIC 모형의 성능을 간접적으로 평가하는 방법을 이용하였다. 본 연구의 결과를 정리하면 다음과 같다. 첫째, 토양수 분의 경년변동은 남한과 북한 모두 전체적으로 유사한 경향을 보였으나, 남한의 토양수분이 북한의 토양수분보다 작게 는 1%에서 크게는 7%까지 높은 것으로 확인되었다. 둘 째, 월 단위 토양수분의 경우, 봄철에 해당하는 4 – 6월의 토 양수분 상태는 남한과 북한에서 유사하게 나타났다. 반면, 장마철 이후 토양수분은 남한의 경우 최대 40%까지 증가하 지만, 북한에서는 최대 32% 정도에 머무르는 것으로 확인되었다. 셋 째, 전체적으로 모의된 토양수분이 인공위성에서 관측된 토양수분보다 약 4% 정도 작지만, 과거 30년 동안 나타난 증가 정도는 위성관측 토양수분과 유사한 것으로 확 인되었다. 마지막으로, 위성관측 토양수분과 VIC 모형으로 유도된 토양수분 자료에 대한 CSEOF를 비교해본 결과, 4 월부터 6월까지의 토양수분은 공간적으로 서로 상당히 다른 패턴을 보이는 것으로 나타났다. 그러나 7월과 10월의 경 우에는 약한 유사성을 보이고 있으며, 8월과 9월은 상당히 유사한 패턴을 가지고 있음을 확인하였다. In this study, land surface model was used to simulate the soil moisture of South and North Korea for the past 30 years, and the difference in their variation was analyzed. In addition, satellite observed soil moisture data provided by Soil Moisture CCI was analyzed to evaluate the simulation results of VIC model. For the comparison between the simulated and observed data, the CSEOF analysis was applied to indirectly assess the performance of the VIC model rather than simply comparing soil moisture values. The results of this study are summarized as follows. First, the annual variability of soil moisture showed a similar tendency in both South and North Korea, but it was found that the soil moisture in South Korea was as high as 1%, up to 7%, higher than the soil moisture in North Korea. Secondly, the soil moisture in spring between April to June is similar in South and North Korea, whereas the soil moisture after the rainy season is up to 40% in South Korea, but remains at maximum 32% in North Korea. Third, the overall simulated soil moisture is about 4% smaller than the satellite observed soil moisture, but the degree of increase over the past 30 years is similar to that of satellite observed soil moisture. Finally, a comparison of the CSEOF from the satellite observed soil moisture and the VIC model derived soil moisture showed that the soil moisture from April to June shows a much different pattern from each other. However, in July and October, there was a slight similarity, and it was confirmed that August and September has quite similar patterns.

탈색 시술 시 수분함유량이 모발 손상에 미치는 영향

김종선 ( Jong-sun Kim ) 한국미용예술경영학회 2015 미용예술경영연구 Vol.9 No.3

Bleaching does much damage to hair and in turn the damaged hair can't be recovered back again. That's why it is important to do damage as little as possible during the operation. Especially, using moisture can make us check the change of hair damage and thus prevent it a little in advance during the bleaching causing heavy hair damage. Healthy hair, of which the dark brown of four level isn't treated by chemicals within recent half year, cleaned by tepid water after shampooing and then dried in its natural state, is selected as experiment material. Also, the damaged hair is used after one more bleaching. Each sample of healthy hair group and damaged hair group is applied with bleaching agent. Then both groups are divided into the former without moisture and the latter with forty to fifty percent of 2g moisture, and leave it in its natural state by towel dry after shampooing for about half-your. Proceed with this experiment, we observe and film it by SEM(Scanning Electron Microscope) and Field Emission type Scanning Electron Microscope(Scanning Electron Microscope, S-4700/Hitachi). After compared to the cases of bleached hair, the bleaching with forty to fifty percent moisture by towel dry shows less cuticle layer damage than that without moisture. In terms of the level of hair, it is found that meaningful difference doesn't occur between the bleaching with moisture and that without moisture. Therefore, we conclude the bleaching with moisture shows similar brightness but less hair damage compared to that without moisture.

Sentinel-1 SAR 데이터를 이용한 우리나라 농지의 토양수분 산출 실험

이수진,홍성욱,조재일,이양원 대한원격탐사학회 2017 大韓遠隔探査學會誌 Vol.33 No.6

Soil moisture plays an important role to affect the Earth’s radiative energy balance and water cycle. In general, satellite observations are useful for estimating the soil moisture content. Passive microwave satellites have an advantage of direct sensitivity on surface soil moisture. However, their coarse spatial resolutions (10-36 km) are not suitable for regional-scale hydrological applications. Meanwhile, in-situ ground observations of point-based soil moisture content have the disadvantage of spatially discontinuous information. This paper presents an experimental soil moisture retrieval using Sentinel-1 SAR (Synthetic Aperture Radar) with 10m spatial resolution for cropland in South Korea. We developed a soil moisture retrieval algorithm based on the technique of linear regression and SVR (support vector regression) using the ground observations at five in-situ sites and Sentinel-1 SAR data from April to October in 2015-2017 period. Our results showed the polarization dependency on the different soil sensitivities at backscattered signals, but no polarization dependence on the accuracies. No particular seasonal characteristics of the soil moisture retrieval imply that soil moisture is generally more affected by hydro-meteorology and land surface characteristics than by phenological factors. At the narrower range of incidence angles, the relationship between the backscattered signal and soil moisture content was more distinct because the decreasing surface interference increased the retrieval accuracies under the condition of evenly distributed soil moisture (during the raining period or on the paddy field). We had an overall error estimate of RMSE (root mean square error) of approximately 6.5%. Our soil moisture retrieval algorithm will be improved if the effects of surface roughness, geomorphology, and soil properties would be considered in the future works. 토양수분은 지구복사에너지평형과 물순환에 영향을 미치는 중요한 인자이므로, 수문학 연구에 있어서 토양수분의 함량을 파악하는 것은 매우 중요하다. 현재 수동형 마이크로파 위성의 토양수분 자료는10~36 km의 저해상도로서 국지규모의 수문분석에 사용하기에는 어려움이 있다. 또한 현장관측 토양수분자료는 지점 자료이므로 공간연속성을 보장하지 못하는 한계가 있다. 이에 본 연구에서는 Sentinel-1의SAR(Synthetic Aperture Radar) 영상을 이용하여 우리나라 농지에서 10 m 해상도의 토양수분 산출 가능성을 살펴보았다. 2015-2017년 4월부터 10월까지 5개의 토양수분 지상관측지점을 대상으로, Sentinel-1 후방산란을 이용하여 선형회귀와 SVR(support vector regression) 방법으로 토양수분 산출을 수행하였다. 편파에 따라 후방산란계수의 토양수분에 대한 민감도가 다르지만, 산출정확도는 VV 편파와 VH 편파가 유사하였다. 토양수분은 식물계절학(phenology)보다는 수문기상과 지면특성에 보다 더 영향을 받기 때문에토양수분 산출에 있어 특별한 계절성은 발견되지 않았다. 대체로 입사각이 작을수록 후방산란과 토양수분간의 관계 패턴이 더 뚜렷하게 나타났으며, 또한 지면에 수분이 충분히 고르게 분포하는 경우 표면 간섭이 줄어들어(시간적으로는 강수시, 공간적으로는 논에서) 산출정확도가 상대적으로 높게 나타났다. 전체적으로RMSE(root mean square error) 6.5% 정도의 오차를 보였으나, 향후 지면 거칠기, 지형, 토성 등 다양한지면 변수의 영향을 반영한다면 보다 더 정확도 높은 토양수분을 산출할 수 있을 것으로 사료된다.

산악지형에서의 CRNP를 이용한 토양 수분 측정 개선을 위한 새로운 중성자 강도 교정 방법 검증 및 평가

조성근,능엔 호앙 하이,정재환,오승철,최민하 대한원격탐사학회 2019 大韓遠隔探査學會誌 Vol.35 No.5

Mesoscale soil moisture measurement from the promising Cosmic-Ray Neutron Probe (CRNP) is expected to bridge the gap between large scale microwave remote sensing and point-based in-situ soil moisture observations. Traditional calibration based on N0 method is used to convert neutron intensity measured at the CRNP to field scale soil moisture. However, the static calibration parameter N0 used in traditional technique is insufficient to quantify long term soil moisture variation and easily influenced by different time-variant factors, contributing to the high uncertainties in CRNP soil moisture product. Consequently, in this study, we proposed a modified traditional calibration method, so-called Dynamic-N0 method, which take into account the temporal variation of N0 to improve the CRNP based soil moisture estimation. In particular, a nonlinear regression method has been developed to directly estimate the time series of N0 data from the corrected neutron intensity. The N0 time series were then reapplied to generate the soil moisture. We evaluated the performance of Dynamic-N0 method for soil moisture estimation compared with the traditional one by using a weighted in-situ soil moisture product. The results indicated that Dynamic-N0method outperformed the traditional calibration technique, where correlation coefficient increased from 0.70 to 0.72 and RMSE and bias reduced from 0.036 to 0.026 and -0.006 to -0.001 m3m-3. Superior performance of the Dynamic-N0 calibration method revealed that the temporal variability of N0 was caused by hydrogen pools surrounding the CRNP. Although several uncertainty sources contributed to the variation of N0 were not fully identified, this proposed calibration method gave a new insight to improve field scale soil moisture estimation from the CRNP. 면 단위의 고해상도 토양 수분 측정이 가능한 Cosmic-Ray Neutron Probe(CRNP)를 이용한 토양수분 관측 데이터는 위성기반의 큰 공간해상도를 지닌 토양 수분 자료와 지점 관측 토양 수분 자료를 연결하는 통로의역할을 수행할 것으로 기대된다. 이러한 CRNP 센서를 이용하여 토양 수분을 산출하기 위해서는 측정된 중성자 강도의 교정이 필요한데 기존의 교정 방법은 관측 기간의 단일 교정 중성자 강도(N0)를 이용하여 장기간의토양 수분 관측에 어려움이 있다. 또한 기존 방법을 이용한 N0는 시간에 따라 변동하는 인자들에 의해 영향을고려하지 못하며 이로 인해 CRNP 센서를 이용한 토양 수분 관측 값에 불확실성을 초래한다. 이를 극복하기 위해 새로운 교정 방법(Dynamic-N0 교정 방법)을 제시한다. Dynamic-N0 교정 방법은 시간에 따른 N0의 변동을 고려함으로써 토양 수분 관측 값을 개선하는 방법으로 비선형 회귀 모델을 이용하여 N0의 시계열 자료를 구하여토양 수분 산출에 이용한다. 본 연구에서는 Dynamic-N0 교정 방법을 이용하여 산출된 토양 수분을 지점 기반토양 수분 및 기존의 교정방법을 이용한 토양 수분 산출 값과 비교하였으며 결과적으로 상관계수를 0.7에서0.72로 개선하였다. RMSE와 Bias는 각각 0.036 m3m-3에서 0.026 m3m-3으로, -0.006 m3m-3에서 -0.001 m3m-3으로 개선되었다. Dynamic-N0 교정 방법의 기존의 방법 대비 탁월한 성능은 CRNP 센서 주변의 수소 공급원에 의하여N0의 변동이 발생했음을 시사한다. 그러나 몇몇 중성자 강도에 영향을 미치는 수소 공급원들에 대한 고려가 구체적으로 이뤄지지 않았는데 이는 향후 연구를 통해 Cosmic-Ray를 이용한 토양 수분 관측이 보다 개선될 수 있음을 보여준다.

토양 내 저장 강수율을 활용한 국내 표층 토양수분 메모리 특성에 관한 연구

김기영,이슬찬,이용준,연민호,이기하,최민하 한국수자원학회 2022 한국수자원학회논문집 Vol.55 No.2

The concept of soil moisture memory was used as a method for quantifying the function of soil to control water flow, which evaluates the average residence time of precipitation. In order to characterize the soil moisture memory, a new measurement index called stored precipitation fraction () was used by tracking the increments in soil moisture by the precipitation event. In this study, the temporal and spatial distribution of soil moisture memory was evaluated along with the slope and soil characteristics of the surface (0~5 cm) soil by using satellite- and model-based precipitation and soil moisture in the Korean peninsula, from 2019 to 2020. The spatial deviation of the soil moisture memory was large as the stored precipitation fraction in the soil decreased preferentially along the mountain range at the beginning (after 3 hours), and the deviation decreased overall after 24 hours. The stored precipitation fraction in the soil clearly decreased as the slope increased, and the effect of drainage of water in the soil according to the composition ratio of the soil particle size was also shown. In addition, average soil moisture contributed to the increase and decrease of hydraulic conductivity, and the rate of rainfall transfer to the depths affected the stored precipitation fraction. It is expected that the results of this study will greatly contribute in clarifying the relationship between soil moisture memory and surface characteristics (slope, soil characteristics) and understanding spatio-temporal variation of soil moisture. 물의 흐름을 제어하는 토양의 기능을 정량적으로 계산하기 위한 방법인 토양수분 메모리(soil moisture memory)는 토양에 도달한 강수가 저장되고 배출되기까지 평균적으로 체류하는 시간을 평가한다. 본 연구에서는 2019, 2020년 한반도 지역에서 강수와 토양수분 위성 기반 모델 산출물을 활용하여 표층(0~5 cm)토양에서의 토양수분 메모리를 산출하고 이를 활용하여 연구지역 내 토양수분 메모리의 시공간적인 분포를 지표면의 경사 및 토양의 특성과 함께 평가하였다. 토양수분 메모리를 특성분석을 위해 강수 사건에 따라 토양수분의 증가를 추적하여 저장 강수율()이라는 새로운 측정 지표를 활용하였다. 강수 발생 초기(3시간 후)에는 산맥을 기준으로 토양 내 저장 강수율이 우선적으로 감소하여 토양수분 메모리의 공간적인 편차가 컸으며 24시간 이후 전반적으로 편차가 감소하였다. 토양 내 저장 강수율은 경사가 증가할수록 감소하는 형태가 뚜렷하게 나타났으며 토양 입자 크기의 구성 비율에 따른 토양 내 수분의 배수 활동에 의한 영향을 확인할 수 있었다. 또한 수리전도도 증감에 기여하는 평균토양수분이 저장 강수율에 미치는 영향을 확인하였다. 본 연구 결과는 강수가 지면에 체류하는 시간에 대한 척도인 토양수분 메모리가 지표의 경사와 토양 특성과 갖는 관계를 규명하고 토양수분의 시공간적 변동성을 이해하는 데 기여할 것으로 기대된다.