Michiaki Sugita, Jingyuan Wang, Chao Zang, F. Kondo
{"title":"A small non-research vessel as a platform for lake surface flux measurements","authors":"Michiaki Sugita, Jingyuan Wang, Chao Zang, F. Kondo","doi":"10.3178/HRL.15.16","DOIUrl":"https://doi.org/10.3178/HRL.15.16","url":null,"abstract":": To study the spatial variability of water surface fluxes, turbulence measurements on a moving platform are useful. However, such measurements have only been carried out with large research vessels over the ocean. We tested the feasibility of flux measurements with a small excursion ship over Lake Kasumigaura, the second largest lake in Japan. After the formal application of coordinate rotations to account for the ship’s movements, we derived mean wind velocities as well as latent and sensible heat fluxes. They were compared with spatially interpolated wind velocities from meteorological stations and with fluxes esti‐ mated from the bulk method. Equally good agreements were found with those reported in previous studies over the ocean, indicating the feasibility of ship measurements in a lake. Possible error sources were identified for the improvement of the accuracy of flux estimation.","PeriodicalId":13111,"journal":{"name":"Hydrological Research Letters","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69394512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Global high-resolution estimation of cropland suitability and its comparative analysis to actual cropland distribution","authors":"Y. Ishikawa, Dai Yamazaki","doi":"10.3178/HRL.15.9","DOIUrl":"https://doi.org/10.3178/HRL.15.9","url":null,"abstract":": Global 500-m (18-arcsec) resolution cropland suitability was estimated using recently developed high-resolution global cropland data and a digital elevation model. The high-resolution estimation more precisely represented topo‐ graphical constraints to agriculture that were not adequately reflected in previous low-resolution estimates. It also suc‐ cessfully suppressed the overestimation of cropland suit‐ ability on areas with steep slopes. Furthermore, the distinc‐ tion of rainfed and irrigated cropland removed suitability overestimation induced by human agricultural intervention and enabled more natural and realistic estimation of crop‐ land suitability. The comparative analysis between the esti‐ mated land suitability and actual cropland distribution revealed that, if only natural condition is considered, it is possible to expand cropland area by 9.25 million km 2 , which is more than needed in the future while socio-economic factors controlling cropland suitability should be considered for more practical assessment. The newly developed highest-resolution cropland suitability map is expected to contribute to solving upcoming water, energy, and food issues, by integrating with water resource models and biomass studies.","PeriodicalId":13111,"journal":{"name":"Hydrological Research Letters","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69394757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Hirabayashi, Haireti Alifu, Dai Yamazaki, Gennadii Donchyts, Yuki Kimura
{"title":"Detectability of variation in river flood from satellite images","authors":"Y. Hirabayashi, Haireti Alifu, Dai Yamazaki, Gennadii Donchyts, Yuki Kimura","doi":"10.3178/hrl.15.37","DOIUrl":"https://doi.org/10.3178/hrl.15.37","url":null,"abstract":"Floods are major natural disasters that have considerable consequences worldwide. As the frequency and magnitude of flooding are expected to be affected by ongoing climate change, understanding their past changes is important for developing adequate adaptation measures. However, the limited spatiotemporal coverage of flood gauges hinders detection of changes in flooding, particularly in poorly gauged regions. Here, we propose a method using surface water data of river floodplain inundation as a proxy of the magnitude and frequency of flooding. Surface water data − Aqua Monitor which represented the probability linear trend changes in land and water surface area based on 30-m Landsat images between 1984–2000 and 2000–2013 was used in this study. The changes in water surface area over the floodplain obtained from Aqua Monitor showed high correspondence with historical trends observed or simulated annual maximum daily discharge, indicating the potential to detect changes in frequency and magnitude of flood from satellite data. In regions where changes could be measured with sufficient satellite images, 29% showed an increase in water surface area in the flood plain, 41% showed a decrease, and 30% showed small or no changes.","PeriodicalId":13111,"journal":{"name":"Hydrological Research Letters","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69394574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Analyzing the bias in dry weather spot flow rates to periodical mean flow rates in mountain streams: toward determining water pollution loads and optimizing water sampling strategies","authors":"Ami Tanno, S. Harada","doi":"10.3178/HRL.15.31","DOIUrl":"https://doi.org/10.3178/HRL.15.31","url":null,"abstract":"Low frequency (once a month) but long-term (ca. 6 years) sampling including snow-melt periods in a moun‐ tainous stream, the Okura River (Sendai, Japan), revealed that loadings of 5 parameters (COD, TN, TP, TOC and DSiO2) could be expressed exponentially using discharge (Q), while the coefficients for the 5 loadings were all about 1. Here, mathematically, the periodically averaged Q leads to approximation of that of load (L). We analyzed the bias of the spot Q to that of the periodical (30, 14 and 8 days) means. The results ensured the utilization of the spot Q instead of the periodical mean Q for estimating L because of the high correlation factors (0.872, 0.914 and 0.923 on 30-, 14-, 8-day mean Q analyses, respectively) and sug‐ gested the validity of the usage of the observed regression slopes of 1.06, 1.22, and 1.22 over 30, 14, 8 days for quan‐ titative correction of L because the fact that the slopes are larger than 1 indicate that the usage of the spot Q instead of the mean Q leads to the overestimation of L. Both changing correlation factors and the regression slopes realized small improvements via shortening the periods from 14 to 8 days. The protocol proposed here is quite original and is applica‐ ble to designing sampling strategies at target sites based on quantification of the limitations and/or reliability of L esti‐ mations.","PeriodicalId":13111,"journal":{"name":"Hydrological Research Letters","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69394566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Hydrological frequency analysis of large-ensemble climate simulation data using control density as a statistical control","authors":"Daiwei Cheng, K. Shimizu, Tomohito J. Yamada","doi":"10.3178/hrl.15.84","DOIUrl":"https://doi.org/10.3178/hrl.15.84","url":null,"abstract":"Uncertainty in hydrological statistics estimated with finite observations, such as design rainfall, can be quanti‐ fied as a confidence interval using statistical theory. Ensemble climate data also enables derivation of a confi‐ dence interval. Recently, the database for policy decision making for future climate change (d4PDF) was developed in Japan, which contains dozens of simulated extreme rain‐ fall events for the past and 60 years into the future, allow‐ ing the uncertainty of design rainfall to be quantified as a confidence interval. This study applies an order statistics distribution to evaluate uncertainty in the order statistics of extreme rainfall from the perspective of mathematical theory, while a confidence interval is used for uncertainty evaluation in the probability distribution itself. An advan‐ tage of the introduction of an order statistics distribution is that it can be used to quantify the goodness-of-fit between observation and ensemble climate data under the condition that the extreme value distribution estimated from observa‐ tions is a true distribution. The order statistics distribution is called the control density distribution, which is derived from characteristics that order statistics from standard uni‐ form distribution follows beta distribution. The overlap ratio of the control density distribution and frequency dis‐ tributions derived from ensemble climate data is utilized for evaluation of the degree of goodness-of-fit for both data.","PeriodicalId":13111,"journal":{"name":"Hydrological Research Letters","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69394747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Matsunaga, N. Matsuo, Takahisa Nakai, N. Yoshifuji, N. Tanaka, Katsunori Tanaka, C. Tantasirin
{"title":"Absorption and emission of water vapor from the bark of teak (Tectona grandis), a deciduous tree, in a tropical region during the dry season","authors":"H. Matsunaga, N. Matsuo, Takahisa Nakai, N. Yoshifuji, N. Tanaka, Katsunori Tanaka, C. Tantasirin","doi":"10.3178/hrl.15.58","DOIUrl":"https://doi.org/10.3178/hrl.15.58","url":null,"abstract":": Changes in stem circumference (SC) were observed in teak ( Tectona grandis ) in a tropical region during the dry season after tree-ring formation had stopped. We hypothe‐ sized that these SC changes were caused by water absorp‐ tion and emission from the outer bark surface. To test this hypothesis, we measured SC, heat pulse velocity (HPV), and leaf number using time series images in a teak tree plantation in northern Thailand. We also performed labora‐ tory experiments to observe changes in the weight and thickness of teak bark blocks under various vapor pressure conditions. Increases in teak tree SC were observed after rainfall during the dry season, when defoliation was almost complete and HPV was low. The weight and thickness of the bark blocks, on which all surfaces other than the outer bark were sealed, varied with water vapor content. These results suggest that water vapor absorption and emission through the outer bark surface can affect SC during the dry season. However, SC continued to increase after the vapor pressure deficit increased, and decreased more rapidly in the tree with higher HPV, suggesting that water exchange between the xylem and inner bark also contributes to changes in SC.","PeriodicalId":13111,"journal":{"name":"Hydrological Research Letters","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69394626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"DEM-based river cross-section extraction and 1-D streamflow simulation for eco-hydrological modeling: a case study in upstream Hiikawa River, Japan","authors":"Tomohiro Tanaka, H. Yoshioka, Y. Yoshioka","doi":"10.3178/hrl.15.71","DOIUrl":"https://doi.org/10.3178/hrl.15.71","url":null,"abstract":": Simulating streamflow under both high-and low-flows is required for versatile eco-hydrological modeling. Typical streamflow simulators require hydrological data such as river geometry and observed river discharge/water level as upstream/downstream boundary conditions. However, these are not always available in data-sparse regions. Further‐ more, because of the potential inaccuracy of digital eleva‐ tion model (DEM) data around water surfaces, this data has not generally been utilized in streamflow simulations. Therefore, this study explores the potential applicability of DEM data to extract river cross-sections, focusing on the upstream Hiikawa River, Japan. A 1-D streamflow simula‐ tion was performed using river cross-sections extracted from a 5 m LiDAR DEM and the observed dam discharge from 2018 to 2020 as the upstream boundary condition. The simulated water depths with Manning’s roughness coefficients of 0.03 to 0.05 m –1/3 s reproduce the observa‐ tion results with Nash-Sutcliffe coefficients of 0.91–0.97 for the whole period and 0.60–0.97 for a flood event. The accurate results for both low and high flows were consid‐ ered to reflect the reasonable representations of the river cross-section. Finally, the velocity-based suitability index for Ayu ( P. altivelis ) was evaluated. We demonstrate appli‐ cability and several possible limitations of DEM data for eco-hydrological modeling of data-scarce rivers.","PeriodicalId":13111,"journal":{"name":"Hydrological Research Letters","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69394643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Guesh Zeru, T. Alamirew, H. Shishaye, Megersa Olmana, N. Tadesse, Michael J. Reading
{"title":"Groundwater level trend analysis using the statistical auto-regressive HARTT method","authors":"Guesh Zeru, T. Alamirew, H. Shishaye, Megersa Olmana, N. Tadesse, Michael J. Reading","doi":"10.3178/hrl.14.17","DOIUrl":"https://doi.org/10.3178/hrl.14.17","url":null,"abstract":"In this study, the Hydrograph Analysis: Rainfall and Time-Trends (HARTT) model was used to determine the contribution of climatic and non-climatic stresses on groundwater levels in the Lake Haramaya well-field, Ethio‐ pia. Monthly precipitation and monitored water-level data were used as explanatory variables of the method. Variabil‐ ity in rainfall explained 81.3% of groundwater levels using 2-month average time-delay. The coefficient of the impact of rainfall on groundwater level (K1) was found to be 0.00562 ± 0.0007 mm. This K1 value indicates that a 1 mm increase in rainfall from the annual average rainfall raises the groundwater-level by 0.00562 ± 0.0007 mm, while 1 mm decrease in rainfall causes a 0.00562 ± 0.0007 mm drop in groundwater-level in the area. However, the aver‐ age falling trend of the groundwater level (K2) was 1.51 ± 0.133 m/year, even with rainfall causing water-levels to rise between 1.01 to 3.29 m/year. With decreased rainfall, rainfall accounted for about 19.5% of the total-drawdown, while 80.5% was due to cumulative effects of non-climatic variables. This shows that rainfall inputs are negated by cumulative non-climatic stresses leading to the long-term net decline in groundwater level. Projected water-level results show that groundwater levels will be below pump‐ ing positions in <24 years which may have dire conse‐ quences for local landowners.","PeriodicalId":13111,"journal":{"name":"Hydrological Research Letters","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2020-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3178/hrl.14.17","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48070792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Matsuyama, Jiei Flores, Kosuke Oikawa, Kengo Miyaoka
{"title":"Comparison of precipitable water via JRA-55 and GPS in Japan considering different elevations","authors":"H. Matsuyama, Jiei Flores, Kosuke Oikawa, Kengo Miyaoka","doi":"10.3178/hrl.14.9","DOIUrl":"https://doi.org/10.3178/hrl.14.9","url":null,"abstract":": This study compared precipitable water vapor (PWV) of JRA-55 and GPS in Japan by considering different eleva‐ tions in JRA-55 (geopotential height) and GPS (antenna height) because JRA-55’s PWV is pointed out to be under‐ estimated as a result of dry bias in the middle and upper troposphere in the forecast model. We selected 26 grid points of JRA-55 over Japanese islands and the respective nearest 26 GPS stations operated by the Geospatial Infor‐ mation Authority of Japan. First, we linearly converted the geopotential height of 26 grid points to air pressure at the antenna height, assuming the sea surface and 1500-m height corresponding to 1013.25 hPa and 850 hPa, respec‐ tively. We then calculated JRA-55’s PWV by vertically integrating specific humidity in the pressure coordinate sys‐ tem using the antenna height from July 2010 through December 2012 (designated as “corrected PWV”). At 22 grid points among the 26, the geopotential height is higher than the antenna height, where the majority of the data of PWV provided by the JRA project was smaller than that retrieved from GPS. The underestimation of the corrected PWV decreased, although 65% of them remained under‐ estimated. The underestimation of the corrected PWV increased in winter and decreased in summer.","PeriodicalId":13111,"journal":{"name":"Hydrological Research Letters","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2020-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3178/hrl.14.9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46230019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Sakaguchi, K. Nakayama, Kenichiro Kobayashi, K. Komai
{"title":"Inundation analysis using coupling storage function model with a distributed hydrological model in Kushiro marsh, Japan","authors":"S. Sakaguchi, K. Nakayama, Kenichiro Kobayashi, K. Komai","doi":"10.3178/hrl.14.75","DOIUrl":"https://doi.org/10.3178/hrl.14.75","url":null,"abstract":": In Kushiro River basin, inundation is likely to occur due to heavy rain, since the river-bed slope is very gentle in the downstream portion, which has natural levees. Conse‐ quently, in past floods, river discharge was observed to increase slowly and a delay of a few days in peak river dis‐ charge was observed compared to the peak precipitation. Therefore, we applied a distributed hydrological model, Geophysical fluid CIRCulation model (GeoCIRC), to reproduce such flood discharge in Kushiro River. GeoCIRC is based on object-oriented programming and various hydrological processes, such as infiltration flow, under‐ ground water flow, surface flow, and river flow can be implemented easily. We proposed a model that can incorpo‐ rate the effect of return flow using storage function by introducing new parameters, such as storage time and time lag. This was done to consider not only the flood inunda‐ tion in Kushiro River but also the return flow from flood inundation to the river flow. As a result, we obtained high Nash-Sutcliffe coefficients for river discharge for two large flood events.","PeriodicalId":13111,"journal":{"name":"Hydrological Research Letters","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69394421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}