Trend Analysis of Temperature Data for Narayani River Basin, Nepal

Sci ◽  
2019 ◽  
Vol 1 (2) ◽  
pp. 38
Author(s):  
Mohan Bahadur Chand ◽  
Bikas Chandra Bhattarai ◽  
Prashant Baral ◽  
Niraj Shankar Pradhananga
Keyword(s):  
Trend Analysis ◽  
River Basin ◽  
Global Climate ◽  
Monsoon Season ◽  
Statistical Significance ◽  
Winter Season ◽  
Temperature Data ◽  
Lapse Rate ◽  
Seasonal Trends ◽  
Temperature Lapse Rate

Study of spatiotemporal dynamics of temperature is vital to assess changes in climate, especially in the Himalayan region where livelihoods of billions of people living downstream depends on water coming from the melting of snow and glacier ice. To this end, temperature trend analysis is carried out in Narayani river basin, a major river basin of Nepal characterized by three climatic regions: tropical, subtropical and alpine. Temperature data from six stations located within the basin were analyzed. The elevation of these stations ranges from 460 to 3800 m a.s.l. and the time period of available temperature data ranges from 1960–2015. Multiple regression and empirical mode decomposition (EMD) methods were applied to fill in missing data and to detect trends. Annual as well as seasonal trends were analyzed and a Mann-Kendall test was employed to test the statistical significance of detected trends. Results indicate significant cooling trends before 1970s, and warming trends after 1970s in the majority of the stations. The warming trends range from 0.028 °C year−1 to 0.035 °C year−1 with a mean increasing trend of 0.03 °C year−1 after 1971. Seasonal trends show highest warming trends in the monsoon season followed by winter, pre-monsoon, and the post-monsoon season. However, difference in warming rates between different seasons was not significant. An average temperature lapse rate of −0.006 °C m−1 with the steepest value (−0.0064 °C m−1) in pre-monsoon season and least negative (−0.0052 °C m−1) in winter season was observed for this basin. A comparative analysis of the gap-filled data with freely available global climate datasets shows reasonable correlation thus confirming the suitability of the gap filling methods.

Trend Analysis of Temperature Data for Narayani River Basin, Nepal

Sci ◽  
2019 ◽  
Vol 1 (2) ◽  
pp. 49
Author(s):  
Mohan Bahadur Chand ◽  
Bikas Chandra Bhattarai ◽  
Niraj Shankar Pradhananga ◽  
Prashant Baral
Keyword(s):  
Trend Analysis ◽  
River Basin ◽  
Global Climate ◽  
Monsoon Season ◽  
Statistical Significance ◽  
Winter Season ◽  
Temperature Data ◽  
Lapse Rate ◽  
Seasonal Trends ◽  
Temperature Lapse Rate

Study of spatiotemporal dynamics of temperature is vital to assess changes in climate, especially in the Himalayan region where livelihoods of billions of people living downstream depends on water coming from the melting of snow and glacier ice. To this end, temperature trend analysis is carried out in Narayani river basin, a major river basin of Nepal characterized by three climatic regions: tropical, subtropical and alpine. Temperature data from six stations located within the basin were analyzed. The elevation of these stations ranges from 460 to 3800 m a.s.l. and the time period of available temperature data ranges from 1960–2015. Multiple regression and empirical mode decomposition (EMD) methods were applied to fill in missing data and to detect trends. Annual as well as seasonal trends were analyzed and a Mann-Kendall test was employed to test the statistical significance of detected trends. Results indicate significant cooling trends before 1970s, and warming trends after 1970s in the majority of the stations. The warming trends range from 0.028 ∘C year−1 to 0.035 ∘C year−1 with a mean increasing trend of 0.03 ∘C year−1 after 1971. Seasonal trends show highest warming trends in the monsoon season followed by winter, pre-monsoon, and the post-monsoon season. However, difference in warming rates between different seasons was not significant. An average temperature lapse rate of −0.006 ∘C m−1 with the steepest value (−0.0064 ∘C m−1) in pre-monsoon season and least negative (−0.0052 ∘C m−1) in winter season was observed for this basin. A comparative analysis of the gap-filled data with freely available global climate datasets show reasonable correlation thus confirming the suitability of the gap filling methods.

scholarly journals Trend Analysis of Temperature Data for the Narayani River Basin, Nepal

Sci ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 1
Author(s):  
Mohan Bahadur Chand ◽  
Bikas Chandra Bhattarai ◽  
Niraj Shankar Pradhananga ◽  
Prashant Baral
Keyword(s):  
Trend Analysis ◽  
River Basin ◽  
Global Climate ◽  
Monsoon Season ◽  
Statistical Significance ◽  
Winter Season ◽  
Temperature Data ◽  
Lapse Rate ◽  
Seasonal Trends ◽  
Temperature Lapse Rate

The study of spatiotemporal variation in temperature is vital to assess changes in climate, especially in the Himalayan region, where the livelihoods of billions of people living downstream depends on water coming from the melting of snow and glacier ice. To this end, temperature trend analysis is carried out in the Narayani River basin, a major river basin of Nepal, characterized by three climatic regions: tropical, subtropical and alpine. Temperature data from six stations located within the basin were analyzed. The elevation of these stations ranges from 460 to 3800 m a.s.l. and the time period of available temperature data ranges from 1960–2015. Multiple regression and empirical mode decomposition (EMD) methods were applied to fill in missing data and to detect trends. Annual as well as seasonal trends were analyzed and a Mann–Kendall test was employed to test the statistical significance of detected trends. The results indicate significant cooling trends before 1970s, and warming trends after 1970s in the majority of the stations. The warming trends range from 0.028 to 0.035 °C year−1 with a mean increasing trend of 0.03 °C year−1 after 1971. Seasonal trends show the highest warming trends in the monsoon season, followed by winter and the premonsoon and postmonsoon season. However, the difference in warming rates between different seasons was not significant. An average temperature lapse rate of −0.006 °C m−1 with the steepest value (−0.0064 °C m−1) in the premonsoon season and the least negative (−0.0052 °C m−1) in the winter season was observed for this basin. A comparative analysis of the gap-filled data with freely available global climate dataset show reasonable correlation, thus confirming the suitability of the gap filling methods.

Trend Analysis of Temperature Data for Narayani River Basin, Nepal

Sci ◽  
2019 ◽  
Vol 1 (1) ◽  
pp. 21 ◽  
Author(s):  
Mohan Chand ◽  
Bikas Bhattarai ◽  
Prashant Baral ◽  
Niraj Pradhananga
Keyword(s):  
Trend Analysis ◽  
River Basin ◽  
Global Climate ◽  
Monsoon Season ◽  
Statistical Significance ◽  
Winter Season ◽  
Temperature Data ◽  
Lapse Rate ◽  
Climate Data ◽  
Seasonal Trends

Study of spatiotemporal dynamics of temperature is vital to assess changes in climate, especially in the Himalayan region where livelihoods of billions of people living downstream depends on water coming from the melting of snow and glacier. To this end, temperature trend analysis is carried out in Narayani river basin, a major river basin of Nepal characterized by three climatic regions: tropical, subtropical and alpine. Temperature data from six stations located within the basin are analyzed. The elevation of these stations ranges from 460 to 3800 m asl. and the time period of available temperature data ranges from 1960–2015. Multiple regression and empirical mode decomposition (EMD) methods are applied to fill in the missing data. Annual as well as seasonal trends are analyzed and Mann-Kendall test is employed for testing the statistical significance of detected trend. Results indicate significant cooling trends before 1970s, and warming trends after 1970s in the majority of the stations. The warming trends range from 0.028 ∘ C per year to 0.035 ∘ C per year with a mean increasing trend of 0.03 ∘ C per year after 1971. Seasonal trends show highest warming trends in monsoon season followed by winter, pre-monsoon, and post-monsoon season. However, difference in warming rates between different seasons isn’t sufficiently large. An average temperature lapse rate of −0.006 ∘ C per m with the steepest value (−0.0064 ∘ C per m) in pre-monsoon season and least negative (−0.0052 ∘ C per m) in winter season is observed for this basin. A comparative analysis of the gap-filled data with freely available global climate data sets shows reasonable correlation thus confirming the suitability of the gap filling methods.

Seasonal Characteristics of Temperature Gradient in a Glaciated Catchment in Eastern Himalaya

2021 ◽  
Vol 7 (3) ◽  
pp. 23-33
Author(s):  
Pradeep Vashisht ◽  
Shresth Tayal
Keyword(s):  
Monsoon Season ◽  
Winter Season ◽  
Lapse Rate ◽  
Eastern Himalaya ◽  
Tree Line ◽  
Temperature Lapse Rate ◽  
Seasonal Characteristics ◽  
Controlling Elements ◽  
Temperature Records ◽  
The Individual

With climatic information from four stations in Rathong Chu valley for the period from 2017 to 2018, this study presents monthly and seasonal characteristics of the temperature lapse rate (TLR) in the eastern Himalayas. The station heights utilised in the study ranged from 1,742 to 4,450 m. The TLRs were assessed utilising a linear regression model. The mean yearly TLR for eastern Himalaya is less sheer (-0.52°C/100 m) beneath the tree line than (-0.47°C/100 m) over the tree line. The series of TLR exhibits two peaks in a year which confirms the distinctive controlling elements in the individual seasons. The highest TLR was found to be -0.60 °C/100 m during the pre-monsoon season below the tree line and -0.64 °C/100 m above the tree line. The post-monsoon has the second highest lapse rate change beneath the tree line (-0.58 °C/100 m) and in the monsoon (-0.57 °C/100 m) above the tree line. The minimum lapse rates were observed in the winter season below the treeline (-0.42 °C/100 m) and (-0.18 °C/100 m) above the tree line. The outcomes of this study add to the insight of elevation-dependent warming affected by worldwide climate change. Results also suggest that the climate and glacier modelling using the satellite temperature records or by applying the environmental lapse rate on temperature records from low altitudes may not be presenting the actual temperature trends.

A new approach for modeling near surface temperature lapse rate based on normalized land surface temperature data

2020 ◽  
Vol 242 ◽  
pp. 111746 ◽  
Author(s):  
Mohammad Karimi Firozjaei ◽  
Solmaz Fathololoumi ◽  
Seyed Kazem Alavipanah ◽  
Majid Kiavarz ◽  
Ali Reza Vaezi ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Temperature Data ◽  
Lapse Rate ◽  
Near Surface ◽  
New Approach ◽  
Temperature Lapse Rate ◽  
Surface Temperature Data

scholarly journals Modeling Seasonal Changes in the Temperature Lapse Rate in a Northern Thailand Mountainous Area

2010 ◽  
Vol 49 (6) ◽  
pp. 1233-1246 ◽  
Author(s):  
Hikaru Komatsu ◽  
Hirofumi Hashimoto ◽  
Tomonori Kume ◽  
Nobuaki Tanaka ◽  
Natsuko Yoshifuji ◽  
...  
Keyword(s):  
Seasonal Changes ◽  
Temperature Data ◽  
Base Stations ◽  
Lapse Rate ◽  
Mountain Forest ◽  
Chiang Mai ◽  
Northern Thailand ◽  
Temperature Lapse Rate ◽  
Regional Circulation ◽  
The Difference

Abstract Temperature data in the mountain forest regions are often extrapolated from temperature data recorded at base stations at lower elevation. Such extrapolation is often based on elevation differences between target regions and base stations at low elevation assuming a constant temperature lapse rate throughout the year. However, this assumption might be problematic where slope circulation is active and decoupled from the regional circulation. To model the seasonal change in the lapse rate, the authors compared daily maximum (Tmax) and minimum temperatures (Tmin) observed at a mountain forest site (Kog–Ma; 1300-m altitude) with those observed at the bottom of the basin (Chiang–Mai; 314-m altitude) in northern Thailand, where slope circulation is active and decoupled from the regional circulation. The difference in Tmax between Kog–Ma and Chiang–Mai (ΔTmax; Kog–Ma minus Chiang–Mai) was relatively unchanged throughout the year. However, the difference in Tmin between Kog–Ma and Chiang–Mai (ΔTmin) changed seasonally. Thus, assuming a constant lapse rate throughout the year could cause large errors in extrapolating Tmin data in mountainous areas in northern Thailand. The difference ΔTmin was related to nighttime net radiation (Rn), suggesting that nocturnal drainage flow affects the determination of ΔTmin. This relationship would be useful in formulating seasonal changes in the lapse rate for Tmin. As Rn data are generally unavailable for meteorological stations, an index that relates to the lapse rate for Tmin and is calculated from Tmax and Tmin data is proposed. This index might be useful for accurately estimating Tmin values in mountainous regions in northern Thailand.

scholarly journals Detection of annual and seasonal temperature variability and change using non-parametric test- A case study of Bundelkhand region of central India

2021 ◽  
Vol 23 (4) ◽  
pp. 402-408
Author(s):  
SUCHIT K. RAI ◽  
SUNIL KUMAR ◽  
MANOJ CHAUDHARY
Keyword(s):  
Climate Change ◽  
Global Climate ◽  
Monsoon Season ◽  
Economic Status ◽  
Winter Season ◽  
Central India ◽  
Warming Trend ◽  
Temperature Variability ◽  
Seasonal Temperature ◽  
Economic Activities

Consequences of global warming and climate change are major threat to humans and their socio-economic activities. Agriculture of Bundelkhand region is supposed to be more vulnerable due to emerging scenario of climate change and poor socio-economic status of farming community. Many studies carried out elsewhere have shown evidence of regional temperature variability along with global climate changes. This study focuses on the temporal variability and trend in annual and seasonal temperature (1901-2012) at six locations of Bundelkhand region. The results of the analysis reveal that the annual maximum (TMax) and minimum (TMin) temperature has significantly increasing trend in all the locations in the range of 0.5 to 2.0oC 100 year-1 and 0.5 to 1.1 oC 100 year-1, respectively. Seasonal analysis revealed warming trend in both TMax (0.6-2.6oC100 year-1) and TMin (0.9 to 2.3 oC 100 year-1) during post-monsoon and winter season in all the locations. Majority of the locations showed cooling trend (0.3-1.0 oC 100 year-1), in the mean maximum and minimum temperature during monsoon season except at two locations i.e Jhansi and Banda. However, a significant positive trends (2.9 oC) in the TMin was found for the period of hundred years at Banda district during monsoon season.

Spatial and temporal variation of surface air temperature at different altitude zone in recent 30 years over Nepal

MAUSAM ◽  
2021 ◽  
Vol 68 (3) ◽  
pp. 417-428
Author(s):  
JANAK LAL NAYAVA ◽  
SUNIL ADHIKARY ◽  
OM RATNA BAJRACHARYA
Keyword(s):  
Air Temperature ◽  
Surface Air Temperature ◽  
Temperature Data ◽  
Lapse Rate ◽  
Spatial And Temporal Variation ◽  
Mountain Regions ◽  
Temperature Lapse Rate ◽  
Air Temperatures ◽  
Long Term Trend

This paper investigates long term (30 yrs) altitudinal variations of surface air temperatures based on air temperature data of countrywide scattered 22 stations (15 synoptic and 7 climate stations) in Nepal. Several researchers have reported that rate of air temperature rise (long term trend of atmospheric warming) in Nepal is highest in the Himalayan region (~ 3500 m asl or higher) compared to the Hills and Terai regions. Contrary to the results of previous researchers, however this study found that the increment of annual mean temperature is much higher in the Hills (1000 to 2000 m asl) than in the Terai and Mountain Regions. The temperature lapse rate in a wide altitudinal range of Nepal (70 to 5050 m asl) is -5.65 °C km-1. Warming rates in Terai and Trans-Himalayas (Jomsom) are 0.024 and 0.029 °C/year respectively.  

scholarly journals Trend Analysis of Rainfall in Prakasam District of Andhra Pradesh State in India

2020 ◽  
pp. 103-110
Author(s):  
M. Satya Swarupa Rani ◽  
R. Asha ◽  
G. M. V. Prasadarao
Keyword(s):  
Trend Analysis ◽  
Crop Production ◽  
Monsoon Season ◽  
Winter Season ◽  
Vital Role ◽  
Precipitation Trend ◽  
Large Variability ◽  
Cropping Patterns ◽  
Climate Analysis

Globally, precipitation trend analysis in different space and time has great impact on crop-planning activities. To get accurate unbiased results a long-term climate analysis of a particular area required in large variability in both spatially, temporally. For sustainable crop production long term weather analysis act as vital role in alternation of existing cropping patterns. This study aimed at analysing the trend of rainfall events in Prakasam district of Andhra state of India the data consists of annual precipitation time series from 1991-2019. Initially study concerns with analysis of data base using descriptive statistics, later trend change was detected by using non parametric tests. The results indicate an increased trend in June and monsoon season, with a decreased trend in July and winter season at 5% level of significance.

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