Indian Ocean moisture flux variations during summer monsoon and its relation with Indian rainfall

1971-1977In this article, we discussed about the variations of moisture flux (MF) over the Indian Ocean (IO) and successive Indian summer monsoon rainfall (ISMR). MF calculated over 1000-850 mb levels at five different sub regions over the IO during 2006-2014. In monsoons months (June through September), moisture transported from the southern IO through Arabian Sea (AS) via a low-level jet produces rainfall in Indian subcontinent. MF commences in May then increases through August and then decreases by September. We verified the relation of five sub regions MF with ISMR and found northwest IO (NWIO), Arabian Sea (AS) have positive relation. However, the Bay of Bengal (BOB) and the central IO (CIO) indicated negative relation. Strong positive relation observed with correlation coefficients (CC) of 0.81 and 0.72 between MF and ISMR over NWIO and AS respectively, however BOB and CIO reveal an inverse relation (CC of –0.34 and -0.7). During an El Nino year, MF deviations are negative over the NWIO and AS, indicating lower moisture transport to India and consecutive ISMR is low. MF during El Nino/La Nina/normal monsoon season over the NWIO and AS areas are important for ISMR

Sea surface temperature cooling induced by Tropical cyclone Hudhud over Bay of Bengal

9-17Hudhud was a very severe cyclone storm occurred in October 2014 over Bay of Bengal (BoB). This paper deals with the sea surface temperature (SST) cooling occurred due to Hudhud. When compared the SST difference between before cyclogenesis and landfall, cooling of 3°C observed. Maximum cooling of SST occurred on 11-12 Oct due to strong winds covered and robust convection all over BoB. Buoy data clearly indicating SST cooling and entrainment of subsurface waters to mixed layer. ARGO data also clearly signifying the SST cooling, however the cooling magnitude is lower (-1.25°C) due to difference in profile timing

Low level jet variations during summer monsoon onset and rainfall variations

1154-1159An attempt has been made to identify low level jet (LLJ) stream influence on Monsoon onset over Kerala (MOK) by considering the wind intensities at 850 hPa over AS (5-20°N and 55-75°E) during the period 1997-2012. The intensity of LLJ confirms an apparent increase after onset; however, rainfall over Kerala is not well correlated with LLJ intensities. During El Nino years, there is a significant positive relation between LLJ and consecutive rainfall after onset

Parameterization of skin-bulk temperature difference in the southeastern Arabian Sea

1769-1773In this study the variation of bulk-skin temperature (∆T) during May-June, has been studied using different methods proposed earlier. To our knowledge, this aspect has not been studied so far for the Arabian Sea or Bay of Bengal. The earlier methods failed to reproduce the variation of ∆T in this region during the period of observations. The following relations are proposed to estimate non-dimensional numerical coefficient λ and skin-bulk temperature variation (∆T).   λ = 1.37*U+9.8 (for the wind speed, 2-8 m/sec)   ∆T= -0.026*Q/U +0.089 Where Q is the sum of latent, sensible and net long wave radiation and U is the wind speed (m/sec). The newly proposed relations are compared with the previously proposed and found that newly developed relation is suitable for Arabian Sea especially for the night time. Root mean Square (RMS) errors (0.2° C) are indicating the performance of newly proposed relations

The Impact of China’s Grain for Green Program on Rural Economy and Precipitation: A Case Study of Yan River Basin in the Loess Plateau

Large-scale deforestation and abandoned planting will bring about the destruction of the ecological environment and the deterioration of the climate. In 1999, China initiated its “Grain for Green” Program (GGP) to improve the ecological environment, control soil erosion, and adjust the agricultural industrial structure to promote the sustainable development of the rural economy. In this paper, economic statistics, rainfall, and remote sensing data are used to analyze the impact of the GGP on agricultural and rural economic development and regional precipitation in the hilly and gully regions of the Loess Plateau. The results show that since the implementation of the program, the employment structure of the labor force has changed and the regional economic growth and farmers’ income have increased. From 2000 to 2016, the total gross domestic product (GDP) and per capita GDP of the Yan River Basin increased. The conversion of large-scale sloping farmland to forestry and grassland resulted in the decrease of farmland area and the increase of forestry area. The maximum, minimum, and mean value of vegetation coverage increased year by year. With the increase of vegetation coverage, the surface roughness, soil water content, and evapotranspiration improved and annual average precipitation grew significantly after the implementation of the program (2000 to 2018). From 1970 to the implementation of the project (1999), the annual average rainfall decreased at the trough from 1988 to 1999, and there was an overall upward trend from 1970 to 2018. The GGP has an important impact on the economy and people’s income in the Yan River Basin, and the vegetation change caused by the variation of land use types has a certain impact on regional rainfall. Under the background of global and regional climate change, it is of great significance to fully understand the impacts of vegetation conversion on climate and its mechanism for objective assessment of driving factors in regional and global climate, as well as for scientific planning of future land use

The use of passive initiation aids in self-propagating high-temperature synthesis

A modification to initiation aid-assisted ignition in bomb calorimetry that involves systemically blending boron and potassium nitrate adjacent to, and within, a bulk structural energetic elemental power blend was developed. Linear regression was used to estimate the nominal heat of reaction for the primary reaction. The technique was applied to the synthesis of TiB2 as a validation study to see if proximity to the literature values could be achieved. X-ray diffraction was used to characterize the product phases of the reactions to determine the extent and the identity of the product phases and any by-products that may have formed as a result of adding the initiation aid. The experimental data indicate the technique approximates the heat of reaction value for the synthesis of TiB2 from Ti/B powder blends and the formation of TiB2 is supported by volume fraction analysis by X-ray diffraction. Some experimental uncertainty remains as X-ray diffraction revealed that the commercially labeled amorphous boron reactant exhibited some crystalline character and may be semicrystalline, as opposed to being completely amorphous. © 2013 The Minerals, Metals & Materials Society and ASM International