Modelling the Climate Change on Crop Estimation in the Semi-Arid Region of Pakistan Using Multispectral Remote Sensing
Zeeshan Zafar,
Shoaib Farooq,
Muhammad Irfan Ahamad,
Muhammad Sajid Mehmood,
Nasir Abbas,
Summar Abbas
Issue:
Volume 9, Issue 1, June 2020
Pages:
1-7
Received:
30 October 2020
Accepted:
23 November 2020
Published:
4 December 2020
Abstract: Remote sensing (RS) is a tool in modern years for the monitoring of crops. Normalized Difference Vegetation Index (NDVI) derived from multi-temporal satellite imagery facilitates the analysis of vegetation growth stage, while comparing it with field/historical departmental yield data. Historical metrological data is also very useful in crop yield estimation especially in arid/semi-arid climatic zones. The metrological conditions including rainfall, humidity, sunshine, and temperature plays vital role in the growth and yield of crops; thus, the climatic conditions can adversely affect the crop yields if are not in accordance with growth requirement of a particular crop. Most of the agricultural land of Punjab province is in semi-arid climatic zone including Chakwal, Jhelum, Mianwali, Khushab, Sargodha, Mandi Bahauddin, Gujranwala, Hafizabad, Shiekhupura, Nankana Sahib, Lahore, Kasur, Faislabad and Chiniot districts. The study will investigate the impact of climate change on wheat crop yields of Chakwal district using advanced RS techniques from 1990 to 2015. Image classification to determine arable and non-arable lands; estimation of changes in temperature using thermal bands of satellite imagery, comparison of historical NDVI profiles; use of climatic data along with nonspatial departmental data for crop yield estimation and drawing its relationship with climatic variables.
Abstract: Remote sensing (RS) is a tool in modern years for the monitoring of crops. Normalized Difference Vegetation Index (NDVI) derived from multi-temporal satellite imagery facilitates the analysis of vegetation growth stage, while comparing it with field/historical departmental yield data. Historical metrological data is also very useful in crop yield e...
Show More
Evaluation of Blue Light Hazard of Luminaires by Spline Function Fitting
Shikang Zhou,
Jin Du,
Shan Li,
Xing Wen,
Xiaoliang He
Issue:
Volume 9, Issue 1, June 2020
Pages:
8-12
Received:
25 October 2020
Accepted:
30 November 2020
Published:
4 December 2020
Abstract: White LEDs are usually excited by blue light. The wide spread use of LED table lamps, made people pay more and more attention to blue light hazard of luminaires. In fact, blue light harms human retina only if irradiation exceeds a certain limit. The problem is therefore to precisely characterize the blue light hazard of a luminaire. In general, blue light hazard is amenable to measurements, but the corresponding detection schemes are complex and expensive. In order to overcome this issue, we put forward a mathematical fitting method to evaluate blue light hazard. It consists of fitting the spectrum of a lamp using spline functions to obtain the lamp brightness. At the same time, spline function approach is also used to obtain the weight function expression of blue light hazard starting from data listed in IEC/EN62471. Finally, a blue light hazard function with wavelength as an independent variable is introduced. The damage due to blue light exposure may be then evaluated by integrating this function. In this way, as long as the absolute light power spectrum of a luminaire is known, quantification of blue light hazard may be directly obtained without measurements. Our method provides a convenient technique to evaluate and analyze the safety level of lamps before production. In order to assess the reliability of our method, we use it to evaluate the blue light hazard of two lamps, which belong to IEC/EN62471 safety level RG0 and RG1 respectively. Results are in good agreement with those measured by authoritative departments. In this way, evaluation of blue light hazard may be obtained by the knowledge of absolute physical properties of the source, a feature which definitely provides an optional approach to assess the photobiological safety of LED lamps.
Abstract: White LEDs are usually excited by blue light. The wide spread use of LED table lamps, made people pay more and more attention to blue light hazard of luminaires. In fact, blue light harms human retina only if irradiation exceeds a certain limit. The problem is therefore to precisely characterize the blue light hazard of a luminaire. In general, blu...
Show More
