scholarly journals Temperature and Precipitation Trend Analysis over the Last 30 Years in Southern Tigray Regional State, Ethiopia

2017 ◽  
Author(s):  
Birhanu Hayelom ◽  
Yingjun Chen ◽  
Zinabu Marsie ◽  
Miseker Negash
Keyword(s):  
Kendall Test ◽  
Warming Trend ◽  
Test Methods ◽  
Annual Precipitation ◽  
Maximum Temperature ◽  
Precipitation Trend ◽  
Southern Zone ◽  
Temperature And Precipitation ◽  
Regional State ◽  
Main Determinants

Long term Precipitation and temperature variations are one of the main determinants of climate variability of one’s area. The aim of this study is to determine trends variation in climatic elements of temperature and precipitation in the southern zone of Tigray regional state, Ethiopia. The station is assumed for the study of climatic records over southern zone of the region in detection for probable trends. The daily, monthly and annual precipitation totals and temperature observed at korem meteorological station were used for the period of 1981-2010 for Precipitation and 1985 – 2010 for minimum and maximum temperature. Summary of descriptive statistics and Mann Kendall test methods were employed for the observed data analysis to demonstrate any existence of possible trends. The main findings of the study indicated that the mean and maximum temperature had a general increasing trend; however, minimum temperature showed decreasing trend. In general annual temperature from 1985 – 2010 of the area showed a warming trend. Moreover analysis of the 30 years (1981-2010) annual precipitation showed a coefficient of variation ranging from 33.77 – 233 %. It indicated that the precipitation dissemination is not normal with large year to year variances.

scholarly journals Cuantificación e interpolación de tendencias locales de temperatura y precipitación en zonas alto andinas de Cundinamarca y Boyacá (Colombia)

2010 ◽  
Vol 11 (2) ◽  
pp. 173 ◽  
Author(s):  
Edwin Rojas ◽  
Blanca Arce ◽  
Andrés Peña ◽  
Francisco Boshell ◽  
Miguel Ayarza
Keyword(s):  
Production Systems ◽  
Hydrological Cycle ◽  
Kendall Test ◽  
Maximum Temperature ◽  
Positive Trend ◽  
Weighted Interpolation ◽  
Weather Patterns ◽  
Statistical Confidence ◽  
Temperature And Precipitation ◽  
Inverse Distance Weighted Interpolation

<p>El cambio en el patrón climático global no sólo afecta la temperatura, sino el ciclo hidrológico con mayores variaciones en los ambientales locales. Con el fin de cuantificar las tendencias de temperatura máxima, mínima y precipitación media, se realizó un análisis no-paramétrico de las series de tiempo de 31 estaciones meteorológicas ubicadas en zonas alto andinas de Cundinamarca y Boyacá, con registros de 1985 a 2008. Se calcularon las tendencias de cambio de las variables climáticas para cada una de las estaciones mediante el método de estimación de pendiente de Sen y se utilizó la prueba de Mann- Kendall para determinar el nivel de confianza de dichas tendencias. La temperatura máxima mostró tendencias positivas con niveles de confianza significativa (&gt;90%) en la mayoría de estaciones climáticas. Para la temperatura mínima, la tendencia positiva fue detectada en menor número de estaciones pero con mayores niveles de confianza estadística (12 estaciones superaron el 95%). La precipitación mostró tendencias significativas (&gt;90%) sólo en siete de las 31 estaciones analizadas (seis de ellas fueron positivas y una negativa). Se utilizó el método de interpolación de distancia inversa ponderada (IDW) para generar los mapas de la distribución espacial de las tendencias. Mediante validación cruzada se encontró que el IDW tiene un mejor ajuste para la precipitación que para la temperatura. Se concluye que el cambio climático tiene manifestaciones muy locales en términos del comportamiento de las temperaturas y la precipitación para la zona de estudio, lo que podría generar impactos específicos sobre los sistemas productivos de la región.</p><p> </p><p><strong>Quantization and interpolation of local trends in temperature and precipitation in the high Andean areas of Cundinamarca and Boyaca (Colombia)</strong></p><p>Change in global weather patterns affects not only temperature, but also the hydrological cycle with greater variations in local environments. In order to quantify trends in maximum temperature and minimum and average precipitation, we performed a nonparametric analysis of time series of 31 meteorological stations located in the high Andes of Cundinamarca and Boyaca, with records from 1985 to 2008. We calculated the changing trends of climatic variables for each of the stations with the Sen slope estimator and we used the Mann-Kendall test to determine the confidence level of such trends. The maximum temperature showed positive trends with significant confidence levels (&gt; 90%) in most seasons. For the lowest temperature, the positive trend was detected in fewer stations but with higher levels of statistical confidence (12 stations exceeded 95%). Rainfall showed significant trends (&gt; 90%) in only seven of the 31 stations analyzed (six of them were positive and one negative). We used the method of inverse distance weighted interpolation (IDW) to generate maps of the spatial distribution of the trends. Cross validation found that IDW has a better fit for precipitation than for temperature. We conclude that climate change manifests very local expressions in terms of the behavior of temperatures and precipitation for the study area, which could lead to specific impacts on production systems in the region.</p>

scholarly journals Time Series Analysis of MODIS-Derived NDVI for the Hluhluwe-iMfolozi Park, South Africa: Impact of Recent Intense Drought

2018 ◽  
Author(s):  
Nkanyiso Mbatha ◽  
Sifiso Xulu
Keyword(s):  
Time Series ◽  
Vegetation Index ◽  
Southern Oscillation ◽  
Kendall Test ◽  
Google Earth ◽  
Maximum Temperature ◽  
Sudden Increase ◽  
Area Index ◽  
Enhanced Vegetation Index ◽  
Temperature And Precipitation

The variability of meteorological parameters such as temperature and precipitation, and climatic conditions such as intense droughts, are known to impact vegetation health over southern Africa. Thus, understanding large-scale ocean&ndash;atmospheric phenomena like the El Ni&ntilde;o/Southern Oscillation (ENSO) and Indian Ocean Dipole/Dipole Mode Index (DMI) is important as these factors drive the variability of temperature and precipitation. In this study, 16 years (2002&ndash;2017) of Moderate Resolution Imaging Spectroradiometer (MODIS) Terra/Aqua 16-day normalized difference vegetation index (NDVI), extracted and processed using JavaScript code editor in the Google Earth Engine (GEE) platform in order to analyze the response pattern of the oldest proclaimed nature reserve in Africa, the Hluhluwe-iMfolozi Park (HiP), during the study period. The MODIS-enhanced vegetation index and burned area index were also analyzed for this period. The area-averaged Modern Retrospective Analysis for Research Application (MERRA) model maximum temperature and precipitation were also extracted using the JavaScript code editor in the GEE platform. This procedure demonstrated a strong reversal of both the NDVI and Enhanced Vegetation Index (EVI), leading to signs of a sudden increase of burned areas (strong BAI) during the strongest El Ni&ntilde;o period. Both the Theilsen method and the Mann&ndash;Kendall test showed no significant greening or browning trends over the whole time series, although the annual Mann&ndash;Kendall test, in 2003 and 2014&ndash;2015, indicated significant browning trends due to the most recent strongest El Ni&ntilde;o. Moreover, a multi-linear regression model seems to indicate a significant influence of both ENSO activity and precipitation. Our results indicate that the recent 2014&ndash;2016 drought altered the vegetation condition in the HiP. We conclude that it is vital to exploit freely available GEE resources to develop drought monitoring vegetation systems, and to integrate climate information for analyzing its influence on protected areas, especially in data-poor counties.

Multi-Time Scale Analysis on Characteristics of Precipitation in Hebei Province

2015 ◽  
Vol 1092-1093 ◽  
pp. 1165-1170 ◽  
Author(s):  
Meng Wang ◽  
Bao Hong Lu ◽  
Han Wen Zhang ◽  
Cong Fei Zhu
Keyword(s):  
Abrupt Change ◽  
Linear Trend ◽  
Kendall Test ◽  
Hebei Province ◽  
Change Points ◽  
Annual Precipitation ◽  
Precipitation Trend ◽  
Multi Scale ◽  
Weather Stations ◽  
Autumn And Winter

Based on the precipitation data observed monthly of 19 weather stations in Hebei province from 1960 to 2011, three methods, linear trend estimation, Mann-Kendall test as well as Morlet wavelet transformation, were adopted to analyze the characteristics of precipitation trend, abrupt change points and cyclical variations under the circumstance of multi-time scales in the past 52 years. Annual precipitation had a decreasing trend, and precipitation in spring increased dramatically, meanwhile precipitation of summer decreased significantly; however, precipitations in autumn and winter were fluctuated in an acceptable range. There were various abrupt change points both in annual precipitation series and in spring as well as in summer, yet any abrupt change points were found in autumn and winter. Multi-scale periodicities were found by wavelet analysis in annual and seasonal precipitations.

scholarly journals Relationship between mean annual temperatures and precipitation sums in Montenegro between 1951-1980 and 1981-2010 periods

2018 ◽  
Vol 98 (1) ◽  
pp. 31-48 ◽  
Author(s):  
Dragan Buric ◽  
Vladan Ducic ◽  
Jovan Mihajlovic
Keyword(s):  
Air Temperature ◽  
21St Century ◽  
Minimum Temperature ◽  
Temperature Fluctuations ◽  
Annual Precipitation ◽  
Maximum Temperature ◽  
Mean Annual Precipitation ◽  
Temperature And Precipitation

In the second half of the 20th and by the beginning of the 21st century the area of Montenegro was dominated by positive air temperature fluctuations and negative precipitation sums. This paper analyses a 60-year period (1951-2010), with the aim to determine air temperature and precipitation deviation between the two 30-year periods: 1951-1980 and 1981-2010. Calculations of mean, mean maximum and mean minimum temperature have been done, as well as annual values of precipitation sums. All three temperature parameters, particularly maximum values, show that the 1981-2010 period was significantly warmer in relation to previous three decades. Significant changes in mean annual precipitation sums between the two observation periods have been recorded on the coast and, locally, in the western part of the country. The results also showed that there was a significant increase in positive deviations of mean maximum temperature in most parts of Montenegro during the 1981-2010 period in relation to the 1951-1980 period, while changes of this type in other observation parameters were mostly minor.

scholarly journals Spatiotemporal Variations of Precipitation over Iran Using the High-Resolution and Nearly Four Decades Satellite-Based PERSIANN-CDR Dataset

2020 ◽  
Vol 12 (10) ◽  
pp. 1584 ◽  
Author(s):  
Hamidreza Mosaffa ◽  
Mojtaba Sadeghi ◽  
Negin Hayatbini ◽  
Vesta Afzali Gorooh ◽  
Ata Akbari Asanjan ◽  
...  
Keyword(s):  
Kendall Test ◽  
Rain Gauge ◽  
Annual Precipitation ◽  
Management Decision ◽  
Monthly Precipitation ◽  
Precipitation Trend ◽  
Climate Data ◽  
Suitable Alternative ◽  
Precipitation Estimation ◽  
Precipitation Trends

Spatiotemporal precipitation trend analysis provides valuable information for water management decision-making. Satellite-based precipitation products with high spatial and temporal resolution and long records, as opposed to temporally and spatially sparse rain gauge networks, are a suitable alternative to analyze precipitation trends over Iran. This study analyzes the trends in annual, seasonal, and monthly precipitation along with the contribution of each season and month in the annual precipitation over Iran for the 1983–2018 period. For the analyses, the Mann–Kendall test is applied to the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Climate Data Record (PERSIANN-CDR) estimates. The results of annual, seasonal, and monthly precipitation trends indicate that the significant decreases in the monthly precipitation trends in February over the western (March over the western and central-eastern) regions of Iran cause significant effects on winter (spring) and total annual precipitation. Moreover, the increases in the amounts of precipitation during November in the south and south-east regions lead to a remarkable increase in the amount of precipitation during the fall season. The analysis of the contribution of each season and month to annual precipitation in wet and dry years shows that dry years have critical impacts on decreasing monthly precipitation over a particular region. For instance, a remarkable decrease in precipitation amounts is detectable during dry years over the eastern, northeastern, and southwestern regions of Iran during March, April, and December, respectively. The results of this study show that PERSIANN-CDR is a valuable source of information in low-density gauge network areas, capturing spatiotemporal variation of precipitation.

scholarly journals Temporal Analysis of Temperature and Precipitation Trends in Shaheed Benazir Abad Sindh, Pakistan

2017 ◽  
Vol 7 (6) ◽  
pp. 2171-2176 ◽  
Author(s):  
S. R. Samo ◽  
N. Bhatti ◽  
A. Saand ◽  
M. A. Keerio ◽  
D. K. Bangwar
Keyword(s):  
Diurnal Temperature Range ◽  
Kendall Test ◽  
Maximum Temperature ◽  
Linear Regression Method ◽  
Positive Trend ◽  
Diurnal Temperature ◽  
Temperature Range ◽  
Temperature And Precipitation ◽  
Mann Kendall Test ◽  
Rainy Days

Temperature and precipitation variations have a huge environmental, social and economic impact. This study aims to analyze the temporal variation of temperature and precipitation in Shaheed Benazir Abad district by using the linear regression method, the trend magnitude, the Mann-Kendall test and the Sen’s estimator of slope. The annual precipitation and monthly temperature data of Shaheed Benazir Abad for the period of 1996-2014 are considered. The result shows that the Diurnal temperature range of all months is decreasing due to the increasing of monthly minimum temperature at a faster rate than the monthly maximum temperature. However, the Diurnal temperature range of extreme events is increasing. The results obtained by using Mann-Kendall test revealed that rainfall exhibits significant positive trend. The trends of rainfall and rainy days show that the amount of rainfall is increasing much more rapidly than that of rainy days which indicates the occurrence of heavy events.

scholarly journals Effects of Recent Climate Change on Maize Yield in Southwest Ecuador

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 299
Author(s):  
Gina Lopez ◽  
Thomas Gaiser ◽  
Frank Ewert ◽  
Amit Srivastava
Keyword(s):  
Climate Change ◽  
Negative Impact ◽  
Kendall Test ◽  
Maize Yield ◽  
Maximum Temperature ◽  
Precipitation Trend ◽  
Growing Period ◽  
Recent Climate Change ◽  
Recent Climate ◽  
Semi Arid

In recent years, evidence of recent climate change has been identified in South America, affecting agricultural production negatively. In response to this, our study employs a crop modelling approach to estimate the effects of recent climate change on maize yield in four provinces of Ecuador. One of them belongs to a semi-arid area. The trend analysis of maximum temperature, minimum temperature, precipitation, wind speed, and solar radiation was done for 36 years (from 1984 to 2019) using the Mann–Kendall test. Furthermore, we simulated (using the LINTUL5 model) the counterfactual maize yield under current crop management in the same time-span. During the crop growing period, results show an increasing trend in the temperature in all the four studied provinces. Los Rios and Manabi showed a decreasing trend in radiation, whereas the semi-arid Loja depicted a decreasing precipitation trend. Regarding the effects of climate change on maize yield, the semi-arid province Loja showed a more significant negative impact, followed by Manabi. The yield losses were roughly 40 kg ha−1 and 10 kg ha−1 per year, respectively, when 250 kg N ha−1 is applied. The simulation results showed no effect in Guayas and Los Rios. The length of the crop growing period was significantly different in the period before and after 2002 in all provinces. In conclusion, the recent climate change impact on maize yield differs spatially and is more significant in the semi-arid regions.

Variability of Some Meteorological Parameters in the Basin of Azov Sea

2020 ◽  
pp. 62-70
Author(s):  
Olesya V. Nazarenko
Keyword(s):  
Summer Precipitation ◽  
Steppe Zone ◽  
Industrial Area ◽  
Warming Trend ◽  
Precipitation Trend ◽  
Temperature And Precipitation ◽  
Azov Sea ◽  
Precipitation Changes ◽  
Term Data

The results of research of trends in temperature and precipitation variability in the Azov sea basin are presented. The territory is an important agricultural and industrial area, the nature of which has undergone major changes. The paper considers changes in temperature and precipitation at stations located mainly in the steppe zone. The analysis of both long – term data and for the period 2001-2015 is carried out. Over the past 15-20 years there have been sig-nificant changes in climate features. A comparative analysis of annual and season changes is given. A steady warming trend has been established. An increase in annual temperatures by 0.4-2.8 °C, January - by 2.6-3.1 °C and July - by 0.7-2.1 °C. The study of air temperature by season showed that winter become warmer by 1.1 (Krasnodar) - 5.8 °C (Gigant). The temperature changed the least in summer in Uryupinsk and Frolovo (0.8-0.9 °C), the most in Krasnodar (2.2 °C). The precipitation trend is less noticeable. There is an increase in the amount of precipitation in the winter and autumn periods. In the spring the amount of precipitation increases for all the stations under unvestigation, with the exception for Voronezh and Chertkovo. In summer precipitation changes complicatedly. A decrease in precipita-tion prevails (Voronezh, Krasnodar, Matveev Kurgan, Taganrog, Gigant, Frolovo, Tsimlyansk) and a slight increase (Chertkovo, Armavir, Rostov, Uryupinsk, and Remontnoye).

scholarly journals Projected Changes in Climate Extremes Using CMIP6 Simulations Over SREX Regions

2021 ◽  
Vol 5 (3) ◽  
pp. 481-497
Author(s):  
Mansour Almazroui ◽  
Fahad Saeed ◽  
Sajjad Saeed ◽  
Muhammad Ismail ◽  
Muhammad Azhar Ehsan ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Extreme Events ◽  
First Century ◽  
Maximum Temperature ◽  
Annual Maximum ◽  
Temperature And Precipitation ◽  
Projected Change ◽  
Twenty First Century ◽  
Projected Changes ◽  
The Tropics

AbstractThis paper presents projected changes in extreme temperature and precipitation events by using Coupled Model Intercomparison Project phase 6 (CMIP6) data for mid-century (2036–2065) and end-century (2070–2099) periods with respect to the reference period (1985–2014). Four indices namely, Annual maximum of maximum temperature (TXx), Extreme heat wave days frequency (HWFI), Annual maximum consecutive 5-day precipitation (RX5day), and Consecutive Dry Days (CDD) were investigated under four socioeconomic scenarios (SSP1-2.6; SSP2-4.5; SSP3-7.0; SSP5-8.5) over the entire globe and its 26 Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX) regions. The projections show an increase in intensity and frequency of hot temperature and precipitation extremes over land. The intensity of the hottest days (as measured by TXx) is projected to increase more in extratropical regions than in the tropics, while the frequency of extremely hot days (as measured by HWFI) is projected to increase more in the tropics. Drought frequency (as measured by CDD) is projected to increase more over Brazil, the Mediterranean, South Africa, and Australia. Meanwhile, the Asian monsoon regions (i.e., South Asia, East Asia, and Southeast Asia) become more prone to extreme flash flooding events later in the twenty-first century as shown by the higher RX5day index projections. The projected changes in extremes reveal large spatial variability within each SREX region. The spatial variability of the studied extreme events increases with increasing greenhouse gas concentration (GHG) and is higher at the end of the twenty-first century. The projected change in the extremes and the pattern of their spatial variability is minimum under the low-emission scenario SSP1-2.6. Our results indicate that an increased concentration of GHG leads to substantial increases in the extremes and their intensities. Hence, limiting CO2 emissions could substantially limit the risks associated with increases in extreme events in the twenty-first century.

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