Measurement report: Variations in surface SO₂ and NO_x mixing ratios from 2004 to 2016 at a background site in the North China Plain

Strict air pollution control strategies have been implemented in recent decades in the North China Plain (NCP), previously one of the most polluted regions in the world, and have resulted in considerable changes in emissions of air pollutants. However, little is so far known about the long-term trends of the regional background level of NOx and SO2, along with the increase and decrease processes of regional emissions. In this study, the seasonal and diurnal variations of NOx and SO2 as well as their long-term trends at a regional background station in the NCP were characterized from 2004 to 2016. On average, SO2 and NOx mixing ratios were 5.7 ± 8.4 ppb and 14.2 ± 12.4 ppb, respectively. The seasonal variations in SO2 and NOx mixing ratios showed a similar pattern with a peak in winter and a valley in summer. However, the diurnal variations in SO2 and NOx mixing ratios greatly differed for all seasons, indicating different sources for SO2 and NOx. Overall, the annual mean SO2 exhibited a significant decreasing trend of ‒6.1 % yr−1 (R = −0.84, P < 0.01) from 2004 to 2016, which is very close to −6.3 % yr−1 of the annual SO2 emission in Beijing, and a greater decreasing trend of −7.4 % yr−1 (R = −0.95, P < 0.01) from 2008 to 2016. The annual mean of NOx showed a fluctuating rise of +3.4 % yr−1 (R = 0.38, P = 0.40) from 2005 to 2010, reaching the peak value (16.9 ppb) in 2010, and then exhibited an extremely significant fluctuating downward trend of −4.5 % yr−1 (R = 0.95, P < 0.01) from 2010 to 2016. After 2010, the annual mean NOx mixing ratios correlated significantly (R = 0.94, P < 0.01) with the annual NOx emission in North China. The decreasing rate (−4.8 % yr−1, R = −0.92, P < 0.01) of the annual mean NOx mixing ratios from 2011 to 2016 at SDZ are lower than the one (−8.8 % yr−1, R = −0.94, P < 0.01) for the annual NOx emission in the NCP and (−9.0 % yr−1, R = −0.96, P < 0.01) in Beijing. It indicated that surface NOx mixing ratios at SDZ had weaker influence than SO2 by the emission reduction in Beijing and its surrounding areas in the NCP. The increase in the amount of motor vehicles led to an increase in traffic emissions for NOx. This study supported conclusions from previous studies that the measures taken for controlling NOx and SO2 in the NCP in the past decades were generally successful. However, NOx emission control should be strengthened in the future.

Døgnvariasjoner for innleggelser ved akuttpsykiatriske enheter

Aim: The aim of this study was to investigate diurnal variations of admissions in acute psychiatry. Method: The registration of 2763 submissions were conducted from 01.04.15–31.12.17 at the University Hospital of North-Norway by completing a form for every admission. Results: The results revealed that a majority of the admissions took place at evening and nighttime. There were significantly (p = .001) more admissions at evening and night. Results revealed that 21,[A1] 5 % (539) of the admissions were between 00:00–08:00, whereas 27,5 % (758) of the admissions were between 08:00–16:00, and 51 % (1409) of the admissions were between 16:00–00:00. Conclusion: The causes behind this distribution of the admissions should be investigated in future studies. Future studies should ask the patients about the causes of the late admissions. Keywords: diurnal variations, admissions, acute psychiatry

An analytical study of thunderstorms over Madras

Individual thunder occasions at Madras (Meenambakkam) during 1981- 1990 have been critically examined and the frequency of thunder occurrence as well as the diurnal variations have been derived. Nature of thunderstorm as revealed in the release of squalls change of temperature and humidity have been explained. Synoptic situations causing the thunder activity at Madras are outlined. Possible guidelines/thumb rules to forecast local severe storms have been attempted and the results are discussed.

A six level automatic soil temperature measuring system

An automatic soil temperature measuring equipment is developed using four terminal thermistors. The output voltages from the six levels, i.e., 10 cm above soil surface, soil surface and 10 cm, 20 cm, 30 cm and 60 cm below the soil surface, are amplified and their multiplexed output is recorded on a chart recorder. The equipment is tested in the field and continuous observations are taken during May 1991. Temperature profiles for different hours of the day are plotted and diurnal variations of all levels are also discussed. An attempt is made to evaluate the damping depth and thence the thermal conductivity and soil heat flux.

Development of intensity based fog climatological information system (daily and hourly) at IGI airport, New Delhi for use in fog forecasting and aviation

The main objective of the present paper is to make a microclimatological study of occurrence of fog of different intensities at Indira Gandhi International (IGI) airport, New Delhi which includes their date-wise climatological probabilities and their corresponding total number of hours of occurrence for 62-days of peak winter from 1st December to 31st January by using hourly visibility data for the period of 1981-2005. Their hourly climatology has been discussed separately for both months using same data for understanding their diurnal variations. Both the computations have been done to find most vulnerable periods with exact dates and timings when both duration and intensity of the fog are very high and hazardous for aviation. Corresponding 10-days and 3-hourly climatology of cumulative fog occurrences are computed to identify a period when fog related flight diversion risk is highest. For better understanding of their variability, dates of extreme hours of occurrences of a particular fog type amongst occurrences of all dates for the period during both months have also been documented. These climatological informations can be used by various airlines for planning flight operation and action for establishment of fog dissipation mechanism. Finally, fogprobability matrices of various intensities based on these climatological data have been presented with dates in first column and hours in the first row for all 62 days of December and January and for all 24 hours of each day giving date and hour wise climatological probability of their occurrences which can be used at IGI as climatological tool for forecasting of fog of various intensity and expected climatological period.

Spatial and Temporal Variations of Aerosol Optical Thickness over the China Seas from Himawari-8

Six years of hourly aerosol optical thickness (AOT) data retrieved from Himawari-8 were used to investigate the spatial and temporal variations, especially diurnal variations, of aerosols over the China Seas. First, the Himawari-8 AOT data were consistent with the AERONET measurements over most of the China Seas, except for some coastal regions. The spatial feature showed that AOT over high latitude seas was generally larger than over low latitude seas, and it is distributed in strips along the coastline and decreases gradually with increasing distance from the coastline. AOT undergoes diurnal variation as it decreases from 9:00 a.m. local time, reaching a minimum at noon, and then begins to increase in the afternoon. The percentage daily departure of AOT over the East China Seas generally ranged ±20%, increasing sharply in the afternoon; however, over the northern part of the South China Sea, daily departure reached a maximum of >40% at 4:00 p.m. The monthly variation in AOT showed a pronounced annual cycle. Seasonal variations of the spatial pattern showed that the largest AOT was usually observed in spring and varies in other seasons for different seas.

Diurnal variations of outgoing long wave radiation (OLR) vis a vis 4 January, 2016 Manipur earthquake (Mw: 6.7): An earthquake precursor?

Daily and diurnal variations of OLR from INSAT 3D and Kalpana satellites have been studied during 25 December, 2015 to 5 January, 2016 over the epicentral region of the Manipur earthquake of 4 January, 2016 (Mw 6.7) and other regions within the view of these satellites. The surface temperatures recorded at Imphal around 30 km from epicentre of this earthquake were also examined. It is found that OLR remained low prior to the occurrence of Manipur earthquake while much larger rise occurred over several other regions where no significant seismic activity was reported. The results corroborate inferences reported in earlier studies that OLR or temperature changes are related to meteorological causes and its sole identification as earthquake precursor may be misleading due to poor constraints.

Diurnal variations in the stratosphere of an ultrahot exoplanet

The temperature profile of a planetary atmosphere is a key diagnostic of radiative and dynamical processes governing the absorption, redistribution, and emission of energy. Observations have revealed dayside stratospheres that either cool [1,2] or warm [3,4] with altitude for a small number of gas giant exoplanets, while others are consistent with constant temperatures [5,6,7,8]. Here we report spectroscopic phase curve measurements for the gas giant WASP-121b,[9] which constrain stratospheric temperatures throughout the diurnal cycle. Variations measured for a water vapor spectral feature reveal a temperature profile that transitions from warming with altitude on the dayside hemisphere to cooling with altitude on the nightside hemisphere. The data are well explained by models assuming chemical equilibrium, with water molecules thermally dissociating at low pressures on the dayside and recombining on the nightside [10,11]. Nightside temperatures are low enough for perovskite (CaTiO3) to condense, which could deplete titanium from the gas phase [12,13] and explain recent non-detections at the day-night terminator [14,15,16,17]. Nightside temperatures are also low enough for refractory species, such as magnesium, iron, and vanadium, to condense. Detections [16,17,18,19] of these metals at the day-night terminator suggest, however, that if they do form nightside clouds, cold trapping is not as effective at removing them from the upper atmosphere. Note: Numbered references have been entered into the "Manuscript Comment" box.