scholarly journals Quantitative accuracy assessment of the revised sparse Gash model using distinct time-step climatic parameters

2021 ◽  
Author(s):  
Yiran Li ◽  
Chuanjie Zhang ◽  
Yong Niu
Keyword(s):  
Accuracy Assessment ◽  
Growing Season ◽  
Northern China ◽  
Climatic Parameters ◽  
Time Step ◽  
Platycladus Orientalis ◽  
Climate Parameters ◽  
Quantitative Accuracy ◽  
Modeling Accuracy ◽  
Event Basis

Abstract Rainfall interception (I) can considerably influence the transport process of water. The revised sparse Gash model (RSGM) is a tool for determining the I, which assumes that the two climate parameters in the model are equal for all storms. However, few studies have provided additional cases to reexamine the correctness of this assumption and investigated the response of I of single storms to the time-step variability in climatic parameters. Hence, running the RSGM separately on an event basis during the growing season in 2017 and using three time-step climatic parameters (storm-based, monthly, and fixed) to estimate I for the forest stands of Pinus tabuliformis, Platycladus orientalis, and Acer truncatum in Northern China. In summary, the modeling accuracy of both cumulative I and individual I was enhanced by increasing the time step of the climatic parameters in this study. These positively support the assumption in the RSGM. These results suggest that it is more appropriate to run the RSGM using fixed climate parameters to estimate I for these tree species during the growing season in northern China. Additionally, the assumption in the RSGM should be appealed to be further confirmed across the widest possible range of species, regions, and time scales.

scholarly journals Environmental Controls of Diurnal and Seasonal Variations in the Stem Radius of Platycladus orientalis in Northern China

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 784 ◽  
Author(s):  
Manyu Dong ◽  
Bingqin Wang ◽  
Yuan Jiang ◽  
Xinyuan Ding
Keyword(s):  
Environmental Factors ◽  
Air Temperature ◽  
Water Status ◽  
Growing Season ◽  
Northern China ◽  
Climate Impacts ◽  
Radial Variation ◽  
Critical Threshold ◽  
Platycladus Orientalis ◽  
Environmental Controls

Fine-resolution studies of stem radial variation over short timescales throughout the year can provide insight into intra-annual stem dynamics and improve our understanding of climate impacts on tree physiology and growth processes. Using data from high-resolution point dendrometers collected from Platycladus orientalis (Linn.) trees between September 2013 and December 2014, this study investigated the daily and seasonal patterns of stem radial variation in addition to the relationships between daily stem radial variation and environmental factors over the growing season. Two contrasting daily cycle patterns were observed for warm and cold seasons. A daily mean air temperature of 0 °C was a critical threshold that was related to seasonal shifts in stem diurnal cycle patterns, indicating that air temperature critically influences diurnal stem cycles. The annual variation in P. orientalis stem radius variation can be divided into four distinct periods including (1) spring rehydration, (2) the summer growing season, (3) autumn stagnation, and (4) winter contraction. These periods reflect seasonal changes in tree water status that are especially pronounced in spring and winter. During the growing season, the maximum daily shrinkage (MDS) of P. orientalis was positively correlated with air temperature (Ta) and negatively correlated with soil water content (SWC) and precipitation (P). The vapor pressure deficit (VPD) also exhibited a threshold-based control on MDS at values below or above 0.8 kPa. Daily radial changes (DRC) were negatively correlated with Ta and VPD but positively correlated with relative air humidity (RH) and P. These results suggest that the above environmental factors are associated with tree water status via their influence on moisture availability to trees, which in turn affects the metrics of daily stem variation including MDS and DRC.

scholarly journals Identifikasi perubahan suhu udara dan curah hujan di Bogor

2020 ◽  
Vol 10 (4) ◽  
pp. 616-626
Author(s):  
Rahmat Hidayat ◽  
Alfi Wardah Farihah
Keyword(s):  
Air Temperature ◽  
Extreme Events ◽  
Climatic Parameters ◽  
West Java ◽  
Climate Parameters ◽  
Increased Temperature ◽  
Temperature Indices ◽  
Consecutive Dry Days

Climate datasets were analyzed to identify the changing climatic parameters and extreme events in Bogor, West Java. This study aims to analyze the characteristic of observational datasets in Baranangsiang and Dramaga, namely, air temperature and rainfall, and to indentify the changing structure of those climate parameters. The analysis has been conducted using RClimdex to understand the long-term changing air temperature and rainfall based on 10 indices for air temperature and 8 indices for rainfall. Results show that the rainfall in Baranangsiang has the daily mean of 10 mm/day and in Dramaga of 8 mm/day. The daily mean of air temperature in Baranangsiang and Dramaga is 27˚C and 25.5˚C, respectively. Generally, the declined slopes of the temperature indices in Barangsiang, namely, TN90p, TNx, TX10p, TNn, TXn, TR20, and SU25, indicate cooler temperature. In Dramaga, the increased temperature indices, namely, TN90p, TX90p, TXx, SU25, and TXn, indicate the warmer temperature. The rainfall indices generally decline, except for CDD, which indicate the increased consecutive dry days in Baranangsiang.   

scholarly journals Characteristics of Horizontal Precipitation in Semi-Humid Forestland in Northern China

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 975
Author(s):  
Jianbo Jia ◽  
Wende Yan ◽  
Xiaoyong Chen ◽  
Wenna Liu
Keyword(s):  
Growing Season ◽  
Northern China ◽  
Formation Mechanisms ◽  
Ecological Significance ◽  
Forest Land ◽  
Mountainous Areas ◽  
Humid Climate ◽  
Climate Region ◽  
Typical Day ◽  
The One

Little information is available on horizontal precipitation in forest land in semi-humid climate regions. In this study, the quantity and duration of horizontal precipitation were investigated using the high precision weighing lysimeter system in the mountainous areas of northern China during the experiment year 2011 and 2012. The purpose of this study was to better understand the formation mechanisms of horizontal precipitation in the semi-humid climate region. The results showed that hourly values of horizontal precipitation distributed between 0 and 0.1 mm, and that the one-night values distributed between 0.2 and 0.4 mm. The number of days with horizontal precipitation accounted for about 45% of the whole year. The average monthly amount of horizontal precipitation was 4.5 mm in the non-growing season, while it was a mere 1.6 mm in the growing season. The total amount of horizontal precipitation in the year was about 33 mm. Horizontal precipitation represented about 4.61% and 4.23% of the annual precipitation in 2011 and 2012. During the non-growing season, water vapor absorbed by the soil was greater than canopy and soil condensation, not only in terms of frequency, but also in the cumulated quantity. On a typical day, the canopy and soil condensation was 0.07 mm, accounting for 31.81% of total quantity of horizontal precipitation (0.22 mm). Air temperature, soil temperature and wind speed were negatively correlated with the quantity and duration of horizontal precipitation. This research could provide information for a better understanding of the ecological significance of horizontal precipitation in the semi-humid climate region in northern China.

Quantitative accuracy assessment of contextually filtered classified images

2001 ◽  
Vol 22 (16) ◽  
pp. 3203-3222 ◽  
Author(s):  
P. M. Zukowskyj ◽  
M. A. Bussell ◽  
C. Power ◽  
R. M. Teeuw
Keyword(s):  
Accuracy Assessment ◽  
Quantitative Accuracy

scholarly journals The response of grassland productivity, soil carbon content and soil respiration rates to different grazing regimes in a desert steppe in northern China

2014 ◽  
Vol 36 (6) ◽  
pp. 573 ◽  
Author(s):  
Xiangyang Hou ◽  
Zhen Wang ◽  
Schellenberg P. Michael ◽  
Lei Ji ◽  
Xiangjun Yun
Keyword(s):  
Soil Respiration ◽  
Soil Carbon ◽  
Net Primary Productivity ◽  
Growing Season ◽  
Northern China ◽  
Rotational Grazing ◽  
Carbon And Nitrogen ◽  
Continuous Grazing ◽  
Significant Difference ◽  
Nitrogen Contents

Soil respiration is a major process for organic carbon losses from arid ecosystems. A field experiment was conducted in 2010 and 2012 on the responses to continuous grazing, rotational grazing and no grazing on desert steppe vegetation in northern China. The growing season in 2010 was relatively dry and in 2012 was relatively wet. The results showed that mean soil respiration was the highest with no grazing in both growing seasons. Compared with no grazing, the soil respiration was decreased by 23.0% under continuous grazing and 14.1% under seasonal rotational grazing. Soil respiration increased linearly with increasing soil water gravimetric content, aboveground net primary productivity (ANPP), belowground net primary productivity (BNPP) and soil carbon and nitrogen contents across the 2 years, whereas a negative correlation was detected between soil respiration and soil temperature. A significant decrease in soil respiration was observed under both continuous grazing and in seasonal rotational grazing in the dry growing season, but no significant difference was detected in the wet growing season. In the wet year, only a non-significant difference in soil respiration was observed between different grazing types. Patterns of seasonal precipitation strongly affected the temporal changes of soil respiration as well as its response to different grazing types. The findings highlight the importance of differences in abiotic (soil temperature, soil water gravimetric content and soil carbon and nitrogen contents) and biotic (ANPP, BNPP and litter mass) factors in mediating the responses of soil respiration to the different grazing regimes.

scholarly journals Impact of Nocturnal Natural Ventilation On the Energy Consumption of Buildings

2017 ◽  
Vol 13 (2) ◽  
pp. 17-26
Author(s):  
Felicia Uciu ◽  
Tiberiu Catalina ◽  
Andreea Vartires ◽  
Iolanda Colda
Keyword(s):  
Energy Consumption ◽  
Energy Efficient ◽  
Natural Ventilation ◽  
Thermal Characteristics ◽  
Thermal Capacity ◽  
Climatic Parameters ◽  
Night Time ◽  
Time Step ◽  
Factors Influencing ◽  
Efficient Measures

Abstract The analysis presented in this paper is dealing with the correct and energy efficient measures of cooling buildings through nocturnal natural ventilation. Using this solution is proved in this article to be efficient and can reduce substantially the cooling demand. In order to establish the factors influencing the process of passively cooling a building (the ventilation volume, exterior temperature, thermal capacity of the building, possible duration of the ventilation), we have chosen different buildings, which we have placed them in different temperature zones of Romania. The study is based on multiple simulations realized with a time step of one hour, with the following variations: the climatic parameters, the thermal characteristics of the building, the air flow during night time, the proposed interior temperature. Since the study consisted of numerous simulations, in order to treat the results we have used statistical methods that cover the practical and possible situations, and proved the efficiency of nocturnal ventilation.

scholarly journals Vegetation greenness response to water availability in northern China from 1982 to 2006

2016 ◽  
Author(s):  
Zhang Fengtai ◽  
An Youzhi
Keyword(s):  
Soil Moisture ◽  
Water Availability ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Growing Season ◽  
Northern China ◽  
Entire Study ◽  
Vegetation Greenness ◽  
Spatio Temporal ◽  
Using Data

Abstract. An evaluation of the relationship between satellite-observed Normalized Difference Vegetation Index (NDVI) data as a proxy for vegetation greenness and water availability (rainfall and soil moisture) can greatly improve our understanding of how vegetation greenness responds to water availability fluctuations. Using Sen and Pearson’s correlation methods, we analyzed the spatio-temporal variation of vegetation greenness for both the entire year and the growing season (GS,4-10) in northern China from 1982 to 2006. Although, vegetation greenness and soil moisture during the study period changed significantly for the entire study area, there was no change in rainfall. Linear correlation analysis between NDVI and rainfall revealed higher correlations using data for all seasons. Higher correlations for NDVI and soil moisture were obtained using growing season data. This study highlights how strongly vegetation greenness responds to water availability dynamics, especially in the growing season period.

Grass habitat analysis and phytolith-based quantitative reconstruction of Asian monsoon climate change in the sand-loess transitional zone, northern China

2019 ◽  
Vol 92 (2) ◽  
pp. 519-529 ◽  
Author(s):  
Hanlin Wang ◽  
Huayu Lu ◽  
Hongyan Zhang ◽  
Shuangwen Yi ◽  
Yao Gu ◽  
...  
Keyword(s):  
Asian Monsoon ◽  
Asian Summer Monsoon ◽  
Regional Scale ◽  
Northern China ◽  
Transitional Zone ◽  
Mean Annual Temperature ◽  
Quantitative Reconstruction ◽  
Climate Parameters ◽  
Habitat Analysis ◽  
Asian Summer

AbstractWe investigated climate niches of grasses at regional scales and quantitatively reconstruct Asian monsoon precipitation at the sand-loess transitional zone in northern China. Our results provide direct evidence that certain grass lineages have been specialized in specific habitats: Pooideae grasses stand out and occupy a much cooler environment than all other subfamilies; Pooideae, Aristidoideae, and Chloridoieae occupy dry environments. Pooideae grasses occupy the coldest and driest environments compared to all other subfamilies, with a mean annual temperature (MAT) and precipitation (MAP) of ~13.6 to ~15.3°C and 224 to ~1674 mm, respectively, at a regional scale. We built a database for grasses and their corresponding climate parameters. Based on this database, past climate parameters at the margin of the Asian summer monsoon since ~70 ka were quantitatively reconstructed by phytolith assemblages. They show that this area was dominated by cold- and dry-adapted grasses since ~70 ka with a MAT and MAP of ~3.3 to ~11.0 °C and ~442 to ~900 mm, respectively, generally consistent with the results of phytolith-based transfer function reconstructions and with the results of previous nearby pollen-based quantitative reconstructions. With the improvement of the species-climate and ecosystem dataset, our database-based method is a promising quantitative reconstruction approach to past climatic change in the monsoon region.

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