Daily Archives: August 24, 2014

Climate data tampering in Australia

WUWT has picked up on the analysis that Jennifer Marohasy has done, which shows how the Australian Bureau of Meteorology has been adjusting raw temperature data to produce an artificial warming trend.” click here

Cloud cover changes determine solar dimming and brightening

Gerald Stanhill, Ori Achiman, Rafael Rosa and Shabtai Cohen. The cause of solar dimming and brightening at the Earth’s surface during the last half century: evidence from measurements of sunshine duration. Journal of Geophysical Research: Atmospheres. Vol. 119 Issue 14 DOI: 10.1002/2013JD021308

Analysis of the Angstrom-Prescott relationship between normalized values of global radiation and sunshine duration measured during the last 50 years made at five sites with a wide range of climate and aerosol emissions showed few significant differences in atmospheric transmissivity under clear or cloud covered skies between years when global dimming occurred and years when global brightening was measured. Nor in most cases were there any significant change in the parameters or in their relationships to annual rates of fossil fuel combustion in the surrounding 1° cells. It is concluded that at the sites studied changes in cloud cover rather than anthropogenic aerosols emissions played the major role in determining solar dimming and brightening during the last half century and that there are reasons to suppose that these findings may have wider relevance.

Click here for full paper (fee).

Ronidazole degradation by chlorination, UV, and UV/Chlorine

Ronidazole is an antiprotozoal agent used in veterinary medicine for the treatment of histomoniasis and swine dysentery.

Qin L, Lin YL, Xu B, Hu CY, Tian FX, Zhang TY, Zhu WQ, Huang H, Gao NY. Kinetic models and pathways of ronidazole degradation by chlorination, UV irradiation and UV/chlorine processes. Water Research. 2014 Aug 6;65C:271-281. doi: 10.1016/j.watres.2014.07.041.

Degradation kinetics and pathways of ronidazole (RNZ) by chlorination (Cl2), UV irradiation and combined UV/chlorine processes were investigated in this paper. The degradation kinetics of RNZ chlorination followed a second-order behavior with the rate constants calculated as (2.13 ± 0.15) × 102 M-2 s-1, (0.82 ± 0.52) × 10-2 M-1 s-1 and (2.06 ± 0.09) × 10-1 M-1 s-1 for the acid-catalyzed reaction, as well as the reactions of RNZ with HOCl and OCl, respectively. Although UV irradiation degraded RNZ more effectively than chlorination did, very low quantum yield of RNZ at 254 nm was obtained as 1.02 × 10-3 mol E-1. RNZ could be efficiently degraded and mineralized in the UV/chlorine process due to the generation of hydroxyl radicals. The second-order rate constant between RNZ and hydroxyl radical was determined as (2.92 ± 0.05) × 109 M-1 s-1. The degradation intermediates of RNZ during the three processes were identified with Ultra Performance Liquid Chromatography – Electrospray Ionization – mass spectrometry and the degradation pathways were then proposed. Moreover, the variation of chloropicrin (TCNM) and chloroform (CF) formation after the three processes were further evaluated. Enhanced formation of CF and TCNM precursors during UV/chlorine process deserves extensive attention in drinking water treatment.

Click here for full paper (fee).