Crop yield in India in relation to EI-Nino

ABSTRACT. Association between the EI- Nino events in the Pacific Ocean and the crop yields in India has been examined. Five districts,viz. Churu, Gwalior, Rewa, Palamau and Bankura located on the normal monsoon trough zone and cultivating altogether different, mostly rainfed crops, were selected for the study. Crop and seasonal rainfall data from 1951-88 were utilised in the analysis. The results indicate that the EI-Nino phenomenon does not exert much influence on the kharif. In wave models with cons crops in India.

A NOVEL VARIATIONAL PERSPECTIVE TO FRACTAL WAVE EQUATIONS WITH VARIABLE COEFFICIENTS

This paper aims at establishing two different types of wave models with unsmooth boundaries by the fractal calculus, and their fractal variational principles are successfully designed by employing the fractal semi-inverse transform method. A new approximate technology is proposed to solve the two fractal models based on the variational principle and fractal two-scale transform method. Finally, two numerical examples show that the proposed method is efficient and accurate, which can be extended to solve different types of fractal models.

Intersecting Linear Light Strands: A Particle Explanation for the Fresnel Central Spot

The Fresnel central spot in a shadow, theorized to be generated from wave interference, has given strong support for wave models of light. Using extended exposure macro imaging in various media, the shadow is shown to be more complex with multiple lines of light intersecting in the center. Using the particle concept of discrete light strands perpendicularly reflecting from a diffraction source, these observations can be more accurately explained. Another quantized aspect of light is shown where linear light strands become rings when an energy threshold is reached.

Estimating Coastal Winds by Assimilating High-Frequency Radar Spectrum Data in SWAN

Many activities require accurate wind and wave forecasts in the coastal ocean. The assimilation of fixed buoy observations into spectral wave models such as SWAN (Simulating Waves Nearshore) can provide improved estimates of wave forecasts fields. High-frequency (HF) radar observations provide a spatially expansive dataset in the coastal ocean for assimilation into wave models. A forward model for the HF Doppler spectrum based on first- and second-order Bragg scattering was developed to assimilate the HF radar wave observations into SWAN. This model uses the spatially varying wave spectra computed using the SWAN model, forecast currents from the Navy Coastal Ocean Model (NCOM), and system parameters from the HF radar sites to predict time-varying range-Doppler maps. Using an adjoint of the HF radar model, the error between these predictions and the corresponding HF Doppler spectrum observations can be translated into effective wave-spectrum errors for assimilation in the SWAN model for use in correcting the wind forcing in SWAN. The initial testing and validation of this system have been conducted using data from ten HF radar sites along the Southern California Bight during the CASPER-West experiment in October 2017. The improved winds compare positively to independent observation data, demonstrating that this algorithm can be utilized to fill an observational gap in the coastal ocean for winds and waves.

Influence of Storm Tidal Current Field and Sea Bottom Slope on Coastal Ocean Waves during Typhoon Malakas

Wave–current interaction in coastal regions is significant and complicated. Most wave models consider the influence of ocean current and water depth on waves, while the influence of the gradient of the sea bottom slope is not taken into account in most research. This study aimed to analyze and quantify the contribution of storm tidal currents to coastal ocean waves in a case where sea bottom slope was not ignored. Fourier analysis was applied to solve the governing equation and boundary conditions, and an analytic model for the calculation of the variation of amplitude of wave orbital motion was proposed. Ocean currents affect ocean waves through resonance. In this paper, an implemented instance of this analytic model was given, using the Shengsi area during Typhoon Malakas as an example. The results suggest that vertical variation in the amplitude of wave orbital motion is remarkable. The impact of wave–current interaction is noticeable where the gradient of the sea bottom slope is relatively large.

The progress of gravitational wave detection in China and its further physical application

Contemporarily, a gravitational wave is one of the most important approaches to gather information from the enormous universe. In short, a gravitational wave is a wave that carries energy, and it is created by the acceleration of massive celestial body propagation with a speed of light. This paper discusses the recent progress of gravitational wave detection in China and clarifies our own opinion on future development. Specifically, a basic description is first presented about the definition and basic knowledge for gravitational wave models and detection methods. Subsequently, this section contains the plan and achievement of the Chinese gravitational wave observatory. Finally, the usages and applications of the gravitational wave to help to detect more phenomena in the universe are demonstrated. These results shed light on a clearer picture of gravitational waves, which may offer a better understanding of the background, principle of detection, and the uses of gravitational waves, i.e., emphasizes its importance in modern astrophysics scientific researches.