Trend Analysis of Long-Term Reference Evapotranspiration and Its Components over the Korean Peninsula

In this study, the spatial and temporal trends of reference evapotranspiration (ETo) and its components consisting of the energy term (ENo) and the aerodynamic term (AEo) were considered over the Korean Peninsula. The T-test and Mann–Kendall (MK) test were used to detect parameter trends after removing the effect of serial correlation from annual and seasonal time series between 1980 and 2017. Due to the lack of solar-radiation data for North Korea (NK), a regionally calibrated model based on South Korea (SK) weather data was developed to estimate daily solar radiation in NK. The results showed that spatial distribution of the ETo increased southward in the range from 705 mm/year in the northeast to 1195 mm/year in the southeast of the Korean Peninsula. The spatial patterns of the ENo and AEo varied from the minimum in the north and increased southward, reaching their maximum values in the southern parts of the Korean Peninsula. The mean annual ETo values of SK and NK were also compared. Over the 37-year period, mean annual evapotranspiration in SK was approximately 18% higher than that in NK. Moreover, mean areal ENo and AEo in SK were higher than in NK. The trend of the ENo on annual and seasonal scales was also upward. In contrast, the trend of the AEo decreased over the Korean Peninsula through all seasons and annual scales. These opposite trends in the ENo and AEo parameters mitigated the significant trends of the ETo. Finally, the stronger significant upward trend of the energy term led to significant increasing trends of ETo on the Korean Peninsula, with ENo being the dominant component in the increase of the ETo.

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Temporal and spatial variability of extreme snowfall indices over northern Xinjiang from 1959/1960 to 2008/2009

Natural Hazards and Earth System Sciences Discussions ◽

10.5194/nhessd-1-7059-2013 ◽

2013 ◽

Vol 1 (6) ◽

pp. 7059-7092 ◽

Cited By ~ 4

Author(s):

S. P. Wang ◽

F. Q. Jiang ◽

R. J. Hu ◽

Y. W. Zhang

Keyword(s):

Temporal Trends ◽

Kendall Test ◽

Winter Precipitation ◽

Kriging Interpolation ◽

Significance Level ◽

Northern Xinjiang ◽

The North ◽

Mk Test ◽

Increasing Trends

Abstract. Plentiful snowfall is an important resource in northern Xinjiang. However, extreme snowfall events can lead to destructive avalanches, traffic interruptions or even the collapse of buildings. The daily winter precipitation data from 18 stations in northern Xinjiang during 1959/1960–2008/2009 were selected for purpose of analyzing long-term variability of extreme snowfall events. Five extreme snowfall indices, Maximum 1 day snowfall amount (SX1day), Maximum 1-weather process snowfall amount (SX1process), Blizzard days (DSb), Consecutive snow days (DSc) and Blizzard weather processes (PSb), were defined and utilized to quantitatively describe the intensity and frequency of extreme snowfall events. Temporal trends of the five indices were analyzed by Mann–Kendall test and simple linear regression, and their trends were interpolated using universal kriging interpolation. Temporally, we found that most stations have upward trends in the five indices of extreme snowfall events, and over entire northern Xinjiang, they were all increasing at the 0.01 significance level (MK test), with the linear tendency rates of 0.49 mm (10 a)−1 (SX1day), 0.89 mm (10 a)−1 (SX1process), 0.024 days (10 a)−1 (DSb), 0.14 days (10 a)−1 (DSc), and 0.069 times (10 a)−1 (PSb) respectively. Meanwhile, obvious decadal fluctuations besides long-term increasing trends are identified. Trends in the intensity and frequency of extreme snowfall events show a~distinct difference spatially. In general, trends of five indices were found shifting from decreasing to increasing from the northeast to the southwest and from the north to the south of northern Xinjiang. Furthermore, the regions covered by increasing or decreasing extreme snowfall events were identified, implying the hot or cold spots for extreme snowfall events changes. These results may be helpful for northern Xinjiang on the regional and local resource and emergency planning.

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Historical and Temporal Trends of Climatic Parameters in North East India

Global NEST Journal ◽

10.30955/gnj.002384 ◽

2017 ◽

Vol 19 (4) ◽

pp. 547-561 ◽

Cited By ~ 3

Keyword(s):

Meteorological Data ◽

Temporal Trends ◽

Maximum Temperature ◽

Local Climate ◽

Water Resources Systems ◽

North East India ◽

North East ◽

Mk Test ◽

Ne India ◽

Increasing Trends

Accessing temporal trend of different meteorological parameters is essential for understanding the local climate changing pattern of a region. Quantitative estimates of the effect of climate change helps in understanding, planning, and management of water resources systems. In this study, monthly meteorological data were collected from 30 stations of north-east (NE) India for 1971–2010 and non-parametric Mann-Kendall (MK) test and Sen slope were employed for detection and quantification of significant temporal trends, respectively. An ESRI ArcGIS toolbar “ArcTrends” was used for the above mentioned tasks. The results obtained for rainfall were of mixed nature and both increasing and decreasing significant trends were found for different stations in different months. Most of the negative trends were found in the months of July–August (monsoon), whereas, more stations showed positive trends in April–May (pre-monsoon), and October–November (post-monsoon), indicating inter-seasonal shifting of rainfall without much change in the annual total. Number of rainy days was found to have positive trends in March–May (pre-monsoon) and negative trends in September–December. Except some positive trends during June–December in Manipur and Meghalaya, there were no significant trends in maximum temperature. In some stations, minimum temperature was found to have significant increasing trends throughout the year indicating a general rising trend in NE India. Some major towns like Guwahati, Imphal, Agartala and Kailashshahar showed significant positive trends in mean temperature, mostly during June–December. Mean relative humidity was, in general, found to be significantly increasing, especially during February–March. In some stations, wind speed was found to have significant negative trends throughout the year, with Agartala being the most affected.

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Comparison of methods for estimation of reference evapotranspiration in North-Central Plateau zone of Odisha

Indian Journal of Agricultural Research ◽

10.18805/ijare.a-4702 ◽

2018 ◽

Author(s):

Rajashree Khatua ◽

S. Pasupalak

Keyword(s):

Water Management ◽

Reference Evapotranspiration ◽

Vital Role ◽

Estimation Methods ◽

Weather Data ◽

Comparison Of Methods ◽

Central Plateau ◽

North Central ◽

The North ◽

Taylor Methods

Estimation of Evapotranspiration is vital role for proper water management and efficient farming activities. A decision support system (DSS_ET) was developed which supports 22 ET0 estimation methods with varied options for calculation of various intermediate parameters. The objective of the study is to estimate ET0 in the North central Plateau zone of Odisha, using weather data of the respective locality and screening of methods to estimate ET0 close to FAO-56 Penman Monteith method. The FAO-24 Penman(c=1) and Turc methods yielded the highest (5.605 mm/day) and the lowest mean ET0 (4.201 mm/day) respectively. For this zone, the highest ET0 values was found to be 10.32 mm/d for FAO-24 Penman(c=1) method followed by Businger-van Bavel (9.73 mm/d) and FAO-PPP-17-Penman (9.68 mm/d) in the month of May, whereas, lowest ET0 value was found in the month of December (2.54 mm/d) for the Priestly-Taylor method followed by 1982 Kimberly-Penman method (3.07 mm/d). Among all the methods, Penman-Monteith and Priestley-Taylor methods were ranked first and tenth respectively. For this zone, correction factor for Penman-Monteith and 1982 Kimberly-Penman methods approaches to one. The FAO-24 Penman (c=1) and Businger-van Bavel methods give more diversion from FAO-56 Penman-Monteith method.

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Elevation-dependent trends in extreme snowfall in the French Alps from 1959 to 2019

10.5194/tc-2021-64 ◽

2021 ◽

Author(s):

Erwan Le Roux ◽

Guillaume Evin ◽

Nicolas Eckert ◽

Juliette Blanchet ◽

Samuel Morin

Keyword(s):

Temporal Trends ◽

Information Criterion ◽

Warming Trend ◽

High Elevation ◽

Extreme Value ◽

Mountain Range ◽

French Alps ◽

The North ◽

Return Levels ◽

Increasing Trends

Abstract. Climate change projections indicate that extreme snowfall are expected to increase in cold areas, i.e. at high latitude and/or high elevation, and to decrease in warmer areas, i.e. at mid-latitude and low elevation. However, the magnitude of these contrasted patterns of change and their precise relations to elevation at the scale of a given mountain range remain ill-known. This study analyzes annual maxima of daily snowfall based on the SAFRAN reanalysis spanning the time period 1959–2019, and provided within 23 massifs in the French Alps every 300 m of elevation. We estimate temporal trends in 100-year return levels with non-stationary extreme value models that depend both on elevation and time. Specifically, for each massif and four elevation ranges (below 1000 m, 1000–2000 m, 2000–3000 m and above 3000 m), temporal trends are estimated with the best extreme value models selected on the basis of the Akaike information criterion. Our results show that a majority of trends are decreasing below 2000 m and increasing above 2000 m. Quantitatively, we find an increase of 100-year return levels between 1959 and 2019 equal to +23 % (+32 kg m−2) on average at 3500 m, and a decrease of −10 % (−7 kg m−2) on average at 500 m. However, for the four elevation ranges, we find both decreasing and increasing trends depending on location. In particular, we observe a spatially contrasted pattern, exemplified at 2500 m: 100-year return levels have decreased in the north of the French Alps while they have increased in the south which may result from interactions between the overall warming trend and circulation patterns. This study has implications for natural hazards management in mountain regions.

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Pneumonia mortality trends in all Brazilian geographical regions between 1996 and 2012

Jornal Brasileiro de Pneumologia ◽

10.1590/s1806-37562016000000235 ◽

2017 ◽

Vol 43 (4) ◽

pp. 274-279

Author(s):

Rosemeire de Olanda Ferraz ◽

Jane Kelly Oliveira-Friestino ◽

Priscila Maria Stolses Bergamo Francisco

Keyword(s):

Temporal Trends ◽

Secondary Data ◽

Mortality Rates ◽

Mortality Trends ◽

Annual Percent Change ◽

Percent Change ◽

The North ◽

Geographical Regions ◽

The One ◽

Increasing Trends

ABSTRACT Objective: To analyze the temporal trends in pneumonia mortality rates (standardized by age, using the 2010 population of Brazil as the standard) in all Brazilian geographical regions between 1996 and 2012. Methods: This was an ecological time-series study examining secondary data from the Mortality Database maintained by the Information Technology Department of the Brazilian Unified Health Care System. Polynomial and joinpoint regression models, and corresponding 95% CIs, were used for trend analysis. Results: The pneumonia mortality rates in the South, Southeast, and Central-West showed a decreasing behavior until 2000, followed by increases, whereas, in the North and Northeast, they showed increasing trends virtually throughout the period studied. There was variation in annual percent change in pneumonia mortality rates in all regions except the North. The Central-West had the greatest decrease in annual percent change between 1996 and 2000, followed by an increase of the same magnitude until 2005. The 80 years and over age group was the one most influencing the trend behavior of pneumonia mortality rates in all regions. Conclusions: In general, pneumonia mortality trends reversed, with an important increase occurring in the years after 2000.

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Statherian (ca. 1714–1680 Ma) Extension-Related Magmatism and Deformation in the Southwestern Korean Peninsula and Its Geological Significance: Constraints from the Petrological, Structural, Geochemical and Geochronological Studies of Newly Identified Granitoids

Minerals ◽

10.3390/min11060557 ◽

2021 ◽

Vol 11 (6) ◽

pp. 557

Author(s):

Byung-Choon Lee ◽

Weon-Seo Kee ◽

Uk-Hwan Byun ◽

Sung-Won Kim

Keyword(s):

Korean Peninsula ◽

Tectonic Setting ◽

Alkali Feldspar ◽

Ductile Deformation ◽

Southwestern Part ◽

The North ◽

Deformation Event ◽

Geochemical Analyses ◽

A Minor ◽

T Values

In this study, petrological, structural, geochemical, and geochronological analyses of the Statherian alkali feldspar granite and porphyritic alkali feldspar granite in the southwestern part of the Korean Peninsula were conducted to examine petrogenesis of the granitoids and their tectonic setting. Zircon U-Pb dating revealed that the two granites formed around 1.71 Ga and 1.70–1.68 Ga, respectively. The results of the geochemical analyses showed that both of the granites have a high content of K2O, Nb, Ta, and Y, as well as high FeOt/MgO and Ga/Al ratios. Both granites have alkali-calcic characteristics with a ferroan composition, indicating an A-type affinity. Zircon Lu-Hf isotopic compositions yielded negative εHf(t) values (−3.5 to −10.6), indicating a derivation from ancient crustal materials. Both granite types underwent ductile deformation and exhibited a dextral sense of shear with a minor extension component. Based on field relationships and zircon U-Pb dating, it was considered that the deformation event postdated the emplacement of the alkali feldspar granite and terminated soon after the emplacement of the porphyritic alkali feldspar granite in an extensional setting. These data indicated that there were extension-related magmatic activities accompanying ductile deformation in the southwestern part of the Korean Peninsula during 1.71–1.68 Ga. The Statherian extension-related events are well correlated with those in the midwestern part of the Korean and eastern parts of the North China Craton.

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Utilising Open Geospatial Data to Refine Weather Variables for Building Energy Performance Evaluation—Incident Solar Radiation and Wind-Driven Infiltration Modelling

Energies ◽

10.3390/en14040802 ◽

2021 ◽

Vol 14 (4) ◽

pp. 802

Author(s):

Kristian Skeie ◽

Arild Gustavsen

Keyword(s):

Solar Radiation ◽

Web Service ◽

Meteorological Data ◽

Surface Wind ◽

Building Energy ◽

Energy Performance ◽

Geospatial Data ◽

Weather Data ◽

Building Site ◽

Incident Solar Radiation

In building thermal energy characterisation, the relevance of proper modelling of the effects caused by solar radiation, temperature and wind is seen as a critical factor. Open geospatial datasets are growing in diversity, easing access to meteorological data and other relevant information that can be used for building energy modelling. However, the application of geospatial techniques combining multiple open datasets is not yet common in the often scripted workflows of data-driven building thermal performance characterisation. We present a method for processing time-series from climate reanalysis and satellite-derived solar irradiance services, by implementing land-use, and elevation raster maps served in an elevation profile web-service. The article describes a methodology to: (1) adapt gridded weather data to four case-building sites in Europe; (2) calculate the incident solar radiation on the building facades; (3) estimate wind and temperature-dependent infiltration using a single-zone infiltration model and (4) including separating and evaluating the sheltering effect of buildings and trees in the vicinity, based on building footprints. Calculations of solar radiation, surface wind and air infiltration potential are done using validated models published in the scientific literature. We found that using scripting tools to automate geoprocessing tasks is widespread, and implementing such techniques in conjunction with an elevation profile web service made it possible to utilise information from open geospatial data surrounding a building site effectively. We expect that the modelling approach could be further improved, including diffuse-shading methods and evaluating other wind shelter methods for urban settings.

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Proposal to Refine Solar Radiation of Typical Meteorological Year Database and Evaluation on the Influence of Air-Conditioning Load

Atmosphere ◽

10.3390/atmos12040524 ◽

2021 ◽

Vol 12 (4) ◽

pp. 524

Author(s):

Jihui Yuan ◽

Kazuo Emura ◽

Craig Farnham

Keyword(s):

Solar Radiation ◽

Air Conditioning ◽

Energy Savings ◽

Energy Resource ◽

Global Solar Radiation ◽

Resource Assessment ◽

Weather Data ◽

Diffuse Solar Radiation ◽

Chinese Standard ◽

The Impact

The Typical meteorological year (TMY) database is often used to calculate air-conditioning loads, and it directly affects the building energy savings design. Among four kinds of TMY databases in China—including Chinese Typical Year Weather (CTYW), International Weather for Energy Calculations (IWEC), Solar Wind Energy Resource Assessment (SWERA) and Chinese Standard Weather Data (CSWD)—only CSWD is measures solar radiation, and it is most used in China. However, the solar radiation of CSWD is a measured daily value, and its hourly value is separated by models. It is found that the cloud ratio (diffuse solar radiation divided by global solar radiation) of CSWD is not realistic in months of May, June and July while compared to the other sets of TMY databases. In order to obtain a more accurate cloud ratio of CSWD for air-conditioning load calculation, this study aims to propose a method of refining the cloud ratio of CSWD in Shanghai, China, using observed solar radiation and the Perez model which is a separation model of high accuracy. In addition, the impact of cloud ratio on air-conditioning load has also been discussed in this paper. It is shown that the cloud ratio can yield a significant impact on the air conditioning load.

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Optimal design of the solar tracking system of parabolic trough concentrating collectors

International Journal of Low-Carbon Technologies ◽

10.1093/ijlct/ctaa065 ◽

2020 ◽

Vol 15 (4) ◽

pp. 613-619

Author(s):

Li Kong ◽

Yunpeng Zhang ◽

Zhijian Lin ◽

Zhongzhu Qiu ◽

Chunying Li ◽

...

Keyword(s):

Numerical Simulation ◽

Solar Radiation ◽

Tracking System ◽

Low Cost ◽

Parabolic Trough ◽

The North ◽

Tracking Mode ◽

Solar Tracking ◽

East West

Abstract The present work aimed to select the optimum solar tracking mode for parabolic trough concentrating collectors using numerical simulation. The current work involved: (1) the calculation of daily solar radiation on the Earth’s surface, (2) the comparison of annual direct solar radiation received under different tracking modes and (3) the determination of optimum tilt angle for the north-south tilt tracking mode. It was found that the order of solar radiation received in Shanghai under the available tracking modes was: dual-axis tracking > north-south Earth’s axis tracking > north-south tilt tracking (β = 15°) > north-south tilt tracking (β = 45) > north-south horizontal tracking > east-west horizontal tracking. Single-axis solar tracking modes feature simple structures and low cost. This study also found that the solar radiation received under the north-south tilt tracking mode was higher than that of the north-south Earth’s axis tracking mode in 7 out of 12 months. Therefore, the north-south tilt tracking mode was studied separately to determine the corresponding optimum tilt angles in Haikou, Lhasa, Shanghai, Beijing and Hohhot, respectively, which were shown as follows: 18.81°, 27.29°, 28.67°, 36.21° and 37.97°.

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Trend Analysis of Annual and Seasonal River Runoff by Using Innovative Trend Analysis with Significant Test

Water ◽

10.3390/w13010095 ◽

2021 ◽

Vol 13 (1) ◽

pp. 95

Author(s):

Yilinuer Alifujiang ◽

Jilili Abuduwaili ◽

Yongxiao Ge

Keyword(s):

Time Series ◽

Trend Analysis ◽

River Runoff ◽

Temporal Trends ◽

Temporal Distribution ◽

Trend Test ◽

Data Series ◽

Mk Test ◽

Comparison Results ◽

Innovative Trend Analysis

This study investigated the temporal patterns of annual and seasonal river runoff data at 13 hydrological stations in the Lake Issyk-Kul basin, Central Asia. The temporal trends were analyzed using the innovative trend analysis (ITA) method with significance testing. The ITA method results were compared with the Mann-Kendall (MK) trend test at a 95% confidence level. The comparison results revealed that the ITA method could effectively identify the trends detected by the MK trend test. Specifically, the MK test found that the time series percentage decreased from 46.15% in the north to 25.64% in the south, while the ITA method revealed a similar rate of decrease, from 39.2% to 29.4%. According to the temporal distribution of the MK test, significantly increasing (decreasing) trends were observed in 5 (0), 6 (2), 4 (3), 8 (0), and 8 (1) time series in annual, spring, summer, autumn, and winter river runoff data. At the same time, the ITA method detected significant trends in 7 (1), 9 (3), 6(3), 9 (3), and 8 (2) time series in the study area. As for the ITA method, the “peak” values of 24 time series (26.97%) exhibited increasing patterns, 25 time series (28.09%) displayed increasing patterns for “low” values, and 40 time series (44.94%) showed increasing patterns for “medium” values. According to the “low”, “medium”, and “peak” values, five time series (33.33%), seven time series (46.67%), and three time series (20%) manifested decreasing trends, respectively. These results detailed the patterns of annual and seasonal river runoff data series by evaluating “low”, “medium”, and “peak” values.

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