scholarly journals Spatial and temporal variations of rainy days and mean daily rainfall intensity in northern Nigeria.

MAUSAM ◽  
2021 ◽  
Vol 44 (1) ◽  
pp. 85-92
Author(s):  
E. O. OLADIPO ◽  
S. SALAHU
Keyword(s):  
Rainfall Intensity ◽  
Daily Rainfall ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Northern Nigeria ◽  
Rainfall Trend ◽  
North Central ◽  
The North ◽  
The Mean ◽  
Rainy Days

The spatial and temporal variations of rainy Gays arid daily rainfall intensity for northern Nigeria for using 54 years data are analysed, The extent and nature of non-random changes, such as trend and fluctuations are Investigated. In general, both, the rainy day frequency and mean daily rainfall intensity decreases northwards except for localized orographic effect in the north central Part of the region. There is statistical evidence or decreasing trend in the, number of rainy days over the period of study, but the trend analysis showed no significance or the mean daily rainfall intensity. This suggests that the recent decreasing rainfall trend In the region particularly In the Sahellan zone, In the result of decrease In the frequency of rainy days and not due to any significant change In the rainfall intensity.  

scholarly journals Assessment of Rainfall Thresholds for Rain-Induced Landslide Activity in North Sikkim Road Corridor in Sikkim Himalaya, India

2019 ◽  
pp. 1-14 ◽  
Author(s):  
Bappaditya Koley ◽  
Anindita Nath ◽  
Subhajit Saraswati ◽  
Kaushik Bandyopadhyay ◽  
Bidhan Chandra Ray
Keyword(s):  
Rainfall Intensity ◽  
Lower Boundary ◽  
Daily Rainfall ◽  
Rainfall Threshold ◽  
Rainfall Data ◽  
Antecedent Rainfall ◽  
Rainfall Thresholds ◽  
Sikkim Himalaya ◽  
North East ◽  
The North

Land sliding is a perennial problem in the Eastern Himalayas. Out of 0.42 million km2 of Indian landmass prone to landslide, 42% fall in the North East Himalaya, specially Darjeeling and Sikkim Himalaya. Most of these landslides are triggered by excessive monsoon rainfall between June and October in almost every year. Various attempts in the global scenario have been made to establish rainfall thresholds in terms of intensity – duration of antecedent rainfall models on global, regional and local scale for triggering of the landslide. This paper describes local aspect of rainfall threshold for landslides based on daily rainfall data in and around north Sikkim road corridor region. Among 210 Landslides occurring from 2010 to 2016 were studied to analyze rainfall thresholds. Out of the 210 landslides, however, only 155 Landslides associated with rainfall data which were analyzed to yield a threshold relationship between rainfall intensity-duration and landslide initiation. The threshold relationship determined fits to lower boundary of the Landslide triggering rainfall events is I = 4.045 D - 0.25 (I=rainfall intensity (mm/h) and D=duration in (h)), revealed that for rainfall event of short time (24 h) duration with a rainfall intensity of 1.82 mm/h, the risk of landslides on this road corridor of the terrain is expected to be high. It is also observed that an intensity of 58 mm and 139 mm for 10-day and 20-day antecedent rainfall are required for the initiation of landslides in the study area. This threshold would help in improvement on traffic guidance and provide safety to the travelling tourists in this road corridor during the monsoon.

scholarly journals Spatial and temporal variations of CO<sub>2</sub> mole fractions observed at Beijing, Xianghe and Xinglong in North China

2021 ◽  
Author(s):  
Yang Yang ◽  
Minqiang Zhou ◽  
Ting Wang ◽  
Bo Yao ◽  
Pengfei Han ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Human Activities ◽  
North China ◽  
Terrestrial Ecosystem ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Boundary Layer Height ◽  
The Mean ◽  
The Impact ◽  
First Time

Abstract. Atmospheric CO2 mole fractions are observed at Beijing (BJ), Xianghe (XH), and Xinglong (XL) in North China using the Picarro G2301 Cavity Ring-Down Spectroscopy instruments. The measurement system is described comprehensively for the first time. The geo-distances among these three sites are within 200 km, but they have very different surrounding environments: BJ is inside the megacity; XH is in the suburban area; XL is in the countryside on a mountain. The mean and standard deviation of CO2 mole fractions at BJ, XH, and XL between October 2018 and September 2019 are 448.4 ± 12.8 ppm, 436.0 ± 9.2 ppm and 420.6 ± 8.2 ppm, respectively. The seasonal variations of CO2 at these three sites are similar, with a maximum in winter and a minimum in summer, which is dominated by the terrestrial ecosystem. However, the seasonal variations of CO2 at BJ and XH are more affected by human activities as compared to XL. By using CO2 at XL as the background, CO2 enhancements are observed simultaneously at BJ and XH. The diurnal variations of CO2 are driven by the boundary layer height, photosynthesis and human activities at BJ, XH and XL. Moreover, we address the impact of the wind on the CO2 mole fractions at BJ and XL. This study provides an insight into the spatial and temporal variations of CO2 mole fractions in North China.

SUMMER TEMPERATURES OF CRYOSOLIC SOILS IN THE NORTH-CENTRAL KEEWATIN, N.W.T.

1980 ◽  
Vol 60 (2) ◽  
pp. 311-327 ◽  
Author(s):  
CHARLES TARNOCAI
Keyword(s):  
Soil Temperature ◽  
Slope Position ◽  
North Central ◽  
Soil Material ◽  
The North ◽  
Soil Temperatures ◽  
Summer Temperatures ◽  
The Mean

Soil temperatures were measured at six depths within 1 m of the surface on 10 Cryosolic soils in the north-central Keewatin area during the summer of 1976. The mean soil temperatures during the study period varied between 1.7 °C and 8.2 °C at a depth of 20 cm and −0.2 °C and 6.0 °C at a depth of 50 cm. The maximum and minimum soil temperatures at a depth of 20 cm ranged from 4.4 °C to 13.9 °C and from −0.6°C to 3.9 °C, respectively, while those at a depth of 50 cm ranged from −0.2 °C to 6.7 °C and from −1.1 °C to 2.2 °C, respectively. During the study period a freeze-back of 30 cm or more occurred from the permafrost on several sites. Soil temperatures were markedly higher where the soil material and vegetation were disturbed. The effects of drainage, soil materials, aspect, slope position, vegetation and peat cover on the soil temperature are discussed.

scholarly journals RAINFALL VARIABILITY IN GUNUNGSEWU KARST AREA, JAVA ISLAND, INDONESIA

2021 ◽  
Vol 8 (1) ◽  
pp. 23-35
Author(s):  
Ahmad Cahyadi ◽  
Eko Haryono ◽  
Tjahyo Nugroho Adji ◽  
Margaretha Widyastuti ◽  
Indra Agus Riyanto ◽  
...  
Keyword(s):  
El Niño ◽  
Rainfall Intensity ◽  
El Nino ◽  
Southern Oscillation ◽  
Meteorological Data ◽  
Rainfall Variability ◽  
Daily Rainfall ◽  
Karst Area ◽  
Annual Rainfall ◽  
Rainy Days

Karst area is highly susceptible to changes to climate parameters. One of the parameters is rainfall variability. In addition to shaping the condition of water resources, rainfall in the Gunung Sewu karst area determines the nature of crop and livestock of the agriculture sectors―the local population's main economic activities, warranting the significance of the rainfall variability studies. Rainfall variability in karst areas also affects disaster conditions such as drought and floods. However, due to insufficient meteorological data in quality and quantity, there has been no rainfall variability studies conducted in this locality. The research intended to analyze rainfall variability in the Gunung Sewu karst area in 1979‒2013 by utilizing rainfall predictions from satellite images that many scholars had tested in different locations and recognized as having good quality. In the analysis, mean monthly rainfall was calculated, and the trends of annual rainfall and average rainfall intensity, dry and rainy seasons, the number of rainy days, and the effect of ENSO (El Niño Southern Oscillation) on rainfall were analyzed. The research data were 35 years of daily rainfall records derived from the National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis (CFSR). The analysis results showed that the mean rainfall, number of rainy days, and rainfall intensity had an increasing trend. Also, El Niño quantitatively influenced the rain in the Gunung Kidul karst area.

scholarly journals Decadal Study of Changing Frequency and Intensity of Rainfall for Selected Locations of Tamil Nadu

2021 ◽  
Vol 16 (3) ◽  
pp. 898-907
Author(s):  
S. KOKILAVANI S. KOKILAVANI ◽  
SP. Ramanathan SP. Ramanathan ◽  
GA. Dheebakaran ◽  
N.K. Sathyamoorthy ◽  
B. Arthirani B. Arthirani ◽  
...  
Keyword(s):  
Tamil Nadu ◽  
Rainfall Intensity ◽  
Rainfall Variability ◽  
Daily Rainfall ◽  
Heavy Rain ◽  
Rainfall Data ◽  
Climatic Extremes ◽  
Increasing Trend ◽  
Research Centres ◽  
Rainy Days

Understanding the pattern of regional climatic extremes is essential for creating an important adaptation measure to safeguard farmers from monsoon tantrums. This paper focuses on the rainfall variability and intensity for spatially different locations of Tamil Nadu. The daily rainfall data over a period of 30 years (1990-2019) for the study locations were collected from the constituent research centres of TNAU. The results indicated that an increasing trend in SWM rainfall was observed in Coimbatore (209.3 to 300.6mm), Ooty (681.4 to 703.1mm), Aduthurai (227.8 to 320.6mm), Kovilpatti (132.8 to 141.3 mm) while the decreasing trend was observed in rest of the places. A decreasing trend was reported in general for all the places during NEM. The decreasing trend in the number of rainy days was registered in Kovilpatti, Virudhunagar and Killikulam that exhibits an alert in modifying the crop planning programme in those areas. The frequency of rainfall intensity revealed that except Ooty, the number of Heavy Rain (HR) to VHR(VHR) was found to be meagre to absent in most of the study locations.

scholarly journals Study of Seasonal Surface Refractivity over North-Central Nigeria

2021 ◽  
pp. 5-13
Author(s):  
Muhammad Ladan ◽  
Oyedum David ◽  
Jibrin Yabagi ◽  
Ndanusa Babakacha ◽  
Mohammed Kimpa ◽  
...  
Keyword(s):  
High Frequency ◽  
Meteorological Data ◽  
Central Zone ◽  
Ground Level ◽  
Weather Conditions ◽  
Very High Frequency ◽  
International Telecommunication Union ◽  
North Central ◽  
The North ◽  
The Mean

Tropospheric radio wave signals experience loss due to multipath effect, scattering and other forms of attenuation through the atmospheric medium, primarily due to variations in weather conditions with time. The knowledge of surface refractivity profile is important for optimal planning of Very High Frequency/Ultra High Frequency (VHF/UHF) terrestrial radio links in a region. The study of surface refractivity (Ns) over the North-Central Nigeria was carried out using meteorological data from seven locations in North-Central zone of Nigeria. The seasonal variations of Ns were also derived using the monthly summaries of surface data obtained from Nigerian Meteorological Agency (NIMET) over seven stations of Abuja, Lafia, Lokoja, Makurdi, Jos, Minna and Ilorin between 2005 and 2010.The results indicated that the monthly averages of radio refractivity during the rainy season months (April to October) are greater than the Ns values during the dry season months (November to March) for all the locations throughout the years of the study. The computed of mean monthly Ns over all the seven stations in the first 1 km above the ground level is 348 N-units, which gives mean refractivity gradient (dN/dh) of -49 N/k, these shows that the region is characterised by low scale super-refraction. The mean k-factor over the entire region in the first 1 km above the ground level is 1.4; the mean Field Strength Variability (FSV) in first 1 km of height in the region was calculated to be 14 dB. The mean Radio Horizon distance within 1 km height for a transmitter height of 100 m over the stations is 42 km. The results provide useful information needed by radio engineers to set up new terrestrial radio propagation links or to improve on the existing ones especially at VHF, UHF in the North-Central region of Nigeria, as recommended by International Telecommunication Union Recommendations (ITU-R P.453, 2013), which observed the need for local reference data on refractivity and refractivity gradients all over the world.

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