Investigating the Effects of Madden-Julian Oscillation on Climate Elements of Iran (1980-2020)

Investigating the Effects of Madden-Julian Oscillation on Climate Elements of Iran (1980-2020)

DOI: 

https://doi.org/10.30564/jasr.v6i2.5351

Abstract

The Madden-Julian Oscillation is one of the large-scale climate change patterns in the maritime tropics, with sub-seasonal time periods of 30 to 60 days affecting tropical and subtropical regions. This phenomenon can cause changes in various quantities of the atmosphere and ocean, such as pressure, sea surface temperature, and the rate of evaporation from the ocean surface in tropical regions. In this research, the effects of Madden-Julian fluctuation on the weather elements of Iran have been investigated with the aim of knowing the effects of different phases in order to improve the quality of forecasts and benefits in territorial planning. At first, the daily rainfall data of 1980-2020 were received from the National Meteorological Organization and quality controlled. Using the Wheeler and Hendon method, the two main components RMM1 and RMM2 were analyzed, based on which the amplitude of the above two components is considered as the main indicator of the intensity and weakness of this fluctuation. This index is based on the experimental orthogonal functions of the meteorological fields, including the average wind levels of 850 and 200 hectopascals and outgoing long wave radiation (OLR) between the latitudes of 20 degrees south and 20 degrees north. The clustering of the 7-day sequence with a component above 1 was used as the basis for clustering all eight phases, and by calculating the abnormality of each phase compared to its long term in the DJF time frame, the zoning of each phase was produced separately. In the end, phases 1, 2, 7, 8 were concluded as effective phases in Iran’s rainfall and phases 3, 4, 5, 6 as suppressive phases of Iran’s rainfall.

Keywords: 

Madden-Julian oscillation, Tropical convection, precipitation, Long-wave radiation, Sub-seasonal oscillation

Comments

Post a Comment

Popular posts from this blog

Impact of Polymer Coating on the Flexural Strength and Deflection Characteristics of Fiber-Reinforced Concrete Beams

Image
Impact of Polymer Coating on the Flexural Strength and Deflection Characteristics of Fiber-Reinforced Concrete Beams DOI:  https://doi.org/10.30564/jbms.v4i2.5304 Abstract Liquid polymers (LP) have become an important structural material used in the construction industry in the last decade. This paper investigates the viability of using commercially available LPs as a coating material to improve the flexural strength of fiber-modified concrete beams. The scope included preparing rectangular prism concrete beams with a concrete mixture including fly ash and fiber and coating them with four different liquid polymers at a uniform thickness following the curing process while one set of samples was maintained under the same conditions as a control group without coating. In addition, cylindrical samples were prepared to determine the compressive strength of the concrete mixture. Following the curing process in an unconfined open-air laboratory environment for another 28 days, concrete sample
Read more

Achieving Sustainable Use and Management of Water Resources for Irrigation in Nigeria

Image
Achieving Sustainable Use and Management of Water Resources for Irrigation in Nigeria DOI:  https://doi.org/10.30564/jees.v2i2.2505 Abstract Water resource is available in Nigeria to meet water demand for domestic, agricultural and industrial use. If well enhanced and protected from various source of pollution. However, less information is available on suitability of water resources for irrigation use in Nigeria. This article reviews literature of the past with regards to influence of geogenic and anthropogenic activities on water resource for irrigation purpose in Nigeria and also to explain the current state of suitability of water resource for irrigation studies in Nigeria and gaps in studies. It also summarizes future ways on water resource management and preventive measure for water resource pollution for irrigation use. Related articles were downloaded from Google scholar in water-related issues. This paper tends to review previous article on water resource in Nigeria, and its su
Read more

Soil Bunds Effect on Soil Properties under Different Topographies of the Southwest Ethiopia

Image
Soil Bunds Effect on Soil Properties under Different Topographies of the Southwest Ethiopia Abstract Soil erosion is a major environmental problem affecting development endeavor. Physical soil and water conservation (SWC) measures such as soil bunds are implemented to mitigate soil erosion. However, information on the effects of soil bunds on soil fertility is limited. This study was aimed to evaluate soil quality in fields with soil bunds and with no soil bunds in steep, middle and lower sloping cultivated lands as well as spatial variation of soil properties in between bunds in southwest Ethiopia. About 7-15 years old bunds and nearby cultivated fields lacking bunds were assessed. From 0 cm-20 cm soil depth, a 36 soil samples were collected. Soil texture, soil organic carbon (SOC), total nitrogen (N tot ) and exchangeable potassium (K exch ) were analyzed. Soil bunds showed significantly ( p <0.0.5) greater clay but less sand than adjacent no-bund fields. In steep, middle, and low
Read more