Avifauna diversity and phenology in a Ramsar site: Lake Tonga (Northeastern Algeria)

Between 2013 and 2016 we conducted an inventory and characterization of aquatic avifauna at Lake Tonga, a Ramsar site. We identified 61 species belonging to 17 families, dominated by Anatidae with 14 species. The inventoried species have different phenological status. Some are known for their regular wintering and some for their summer concentrations, while others are residents year round. Population analysis showed the presence of endangered species such as Oxyura leucocephala, Marmaronetta angustirostris and Aythya nyroca, that are protected by national and/or international laws. Bird counts showed monthly variations in total abundance and richness, peaking during winter. Peak numbers were recorded in February and January, reflecting gatherings to prepare for prenuptial migration. Analysis of diversity and equitability indices indicated that maximum values ​​were generally recorded during the pre– and post–nuptial passages (H’= 3.51 and E = 0.72). Our results reflect the importance of this wetland as a wintering site and nesting site for numerous waterbirds species.

The Storage of Antecedent Precipitation and Air Temperature Signals in Soil Temperature over China

Soil temperature (ST) is one of the key variables in land-atmosphere interactions. The response of ST to atmospheric changes and subsequent influence of ST on atmosphere can be recognized as the processes of signals propagation. Understanding the storing and releasing of atmosphere signals in ST favors the improvement of climate prediction and weather forecast. However the current understanding of the lagging response of ST to atmospheric changes is very insufficient. The analysis based on observation shows that both the storage of air temperature signals in deep ST even after four months and the storage of precipitation signals in shallow ST after one month are widespread phenomena in China. Air temperature signals at 2m can propagate to the soil depths of 160 cm and 320 cm after 1 month and 2 months, respectively. The storage of antecedent air temperature and precipitation signals in ST is slightly weaker and stronger during April to September, respectively, which is related to more precipitation during growing season. The precipitation signals in ST rapidly weaken after 2 months. Moreover, the effects of accumulated precipitation and air temperature on the signal storage in ST have significant monthly variations and vary linearly with soil depth and latitude. The storage of antecedent air temperature or precipitation signals in ST exhibits an obvious decadal variation with a period of more than 50 years, and it may be resulted from the modulation of the global climate patterns which largely affect local air temperature and precipitation.

A Study of Solar Flare Effects on the Geomagnetic Field Components during Solar Cycles 23 and 24

In this paper, we investigated the impact of solar flares on the horizontal (H), eastward (Y) and vertical (Z) components of the geomagnetic field during solar cycles 23 and 24 (SC23/24) using data of magnetometer measurements on the sunlit side of the Earth. We examined the relation between sunspot number and solar flare occurrence of various classes during both cycles. During SC23/24, we obtained correlation coefficient of 0.93/0.97, 0.96/0.96 and 0.60/0.56 for C-class, M-class and X-class flare, respectively. The three components of the geomagnetic field reached a peak a few minutes after the solar flare occurrence. Generally, the magnetic crochet of the H component was negative between the mid-latitudes and Low-latitudes in both hemispheres and positive at low latitudes. By contrast, the analysis of the latitudinal variation of the Y and Z components showed that unlike the H component, their patterns of variations were not coherent in latitude. The peak amplitude of solar flare effect (sfe) on the various geomagnetic components depended on many factors including the local time at the observing station, the solar zenith angle, the position of the station with respect to the magnetic equator, the position of solar flare on the sun and the intensity of the flare. Thus, these peaks were stronger for the stations around the magnetic equator and very low when the geomagnetic field components were close to their nighttime values. Both cycles presented similar monthly variations with the highest sfe value (ΔHsfe = 48.82 nT for cycle 23 and ΔHsfe = 24.68 nT for cycle 24) registered in September and lowest in June for cycle 23 (ΔHsfe = 8.69 nT) and July for cycle 24 (ΔHsfe = 10.69 nT). Furthermore, the sfe was generally higher in cycle 23 than in cycle 24.

Diagnosis of ecological quality of Dohou Lake on the basis of environmental parameters and phytoplankton community, Western Côte d’Ivoire

The ecological quality of Dohou Lake in Duékoué was determined from the phytoplankton community and physico-chemical parameters. All of the stations in Dohou Lake are dominated by Cyanobacteria and Bacillariophyta individuals, with high monthly proportions observed during the study period. Ecological indicators such as total phosphorus, transparency and chlorophyll made it possible to assess the physico-chemical quality of the environment. Thus, mean total phosphorus values ranged from 970 to 1150 µg/L from station D7 to station D6. Minimum transparency values ranged from 0.1 to 0.5 m from station D7 to D3, and mean values ranged from 0.3 m (station D7) to 0.69 m (station D1). For chlorophyll a, mean values ranged from 3.52 µg/L to 12.98 µg/L from station D7 to station D2, with maximum values for this parameter ranging from 13.4 µg/L (station D7) to 46.73 µg/L (station D2). All of the stations on Dohou lake are therefore in an eutrophic state. The monthly variations in the different proportions of phytoplankton groups observed indicate a clear predominance of Cyanobacteria followed by Bacillariophyta. The values of the Planktonic Index (PI) indicate that the stations are in average ecological condition, except for station D7, which is in poor ecological condition. These ecological qualities are reflected by the spatial and temporal dominance of 4 functional groups which are C, LM, K, and S1.

A meso-scale study of groundwater fluctuations of Delhi in relation to rainfall

A study of groundwater level at Delhi in relation to rainfall has been conducted. Groundwater data for the period 1956 to 1966 in respect of 97 bores/holes in Delhi have been processed and synchronised and maps of mean ground-water level for urban Delhi have been prepared at fortnightly intervals for the monsoon period and at monthly intervals for the remaining months of the year. Monthly variations of groundwater levels against distance from river Yamuna have been studied and the distribution of the groundwater slope evaluated. Inter-relationship between the rainfall arid the groundwater levels has been studied graphically. A regression equation for the estimation of fortnightly groundwater level fluctuations from rainfall amount, duration of rainfall and the level of water in river Yamuna has been formulated and tested for its applicability.

A data fusion approach to the estimation of temporary populations: An application to Australia

This study establishes a new method for estimating the monthly Average Population Present (APP) in Australian regions. Conventional population statistics, which enumerate people where they usually live, ignore the significant spatial mobility driving short term shifts in population numbers. Estimates of the temporary or ambient population of a region have several important applications including the provision of goods and services, emergency preparedness and serve as more appropriate denominators for a range of social statistics. This paper develops a flexible modelling framework to generate APP estimates from an integrated suite of conventional and novel data sources. The resultant APP estimates reveal the considerable seasonality in small area populations across Australia’s regions alongside the contribution of domestic and international visitors as well as absent residents to the observed monthly variations. The modelling framework developed in the paper is conceived in a manner such that it can be adapted and re-deployed both for use with alternative data sources as well as other situational contexts for the estimation of temporary populations.

A Study on Phyto-Chemical Analysis and Antibacterial Activity of Spices on Pathogenic Bacteria Isolated from Commercially Important Edible Marine Fishes, Euthynnus Affinis (Cantor), Katsuwonus Pelamis L. and Auxis Thazard (Lacepede) (Family Scombridae)

Ten bacterial species were isolated and monthly variations in their count were recorded from three edible tuna fishes. Phytochemical analysis and antibacterial activity of hexane, chloroform, methanol, and distilled water extracts of twelve common spices, against the isolated bacteria were evaluated. The study indicates that these pathogenic bacteria in all three tuna fish species cause various human health problems upon consumption.

Retrieval of O3, NO2, BrO and OClO Columns from Ground-Based Zenith Scattered Light DOAS Measurements in Summer and Autumn over the Northern Tibetan Plateau

Ground-based zenith scattered light differential optical absorption spectroscopy (DOAS) measurements were performed in summer and autumn (27 May–30 November) 2020 at Golmud (94°54′ E, 36°25′ N; 2807.6 m altitude) to investigate the abundances and temporal variations of ozone (O3) and its depleting substances over the northern Tibetan Plateau (TP). The differential slant column densities (dSCDs) of O3, nitrogen dioxide (NO2), bromine monoxide (BrO), and chlorine dioxide (OClO) were simultaneously retrieved from scattered solar spectra in the zenith direction during the twilight period. The O3 vertical column densities (VCDs) were derived by applying the Langley plot method, for which we investigated the sensitivities to the chosen wavelength, the a-priori O3 profile and the aerosol extinction profile used in O3 air mass factor (AMF) simulation as well as the selected solar zenith angle (SZA) range. The mean O3 VCDs from June to November 2020 are 7.21 × 1018 molec·cm−2 and 7.18 × 1018 molec·cm−2 at sunrise and sunset, respectively. The derived monthly variations of the O3 VCDs, ranging from a minimum of 6.9 × 1018 molec·cm−2 in October to 7.5 × 1018 molec·cm−2 in November, well matched the OMI satellite product, with a correlation coefficient R = 0.98. The NO2 VCDs at SZA = 90°, calculated by a modified Langley plot method, were systematically larger at sunset than at sunrise as expected with a pm/am ratio of ~1.56. The maximum of the monthly NO2 VCDs, averaged between sunrise and sunset, was 3.40 × 1015 molec·cm−2 in July. The overall trends of the NO2 VCDs were gradually decreasing with the time and similarly observed by the ground-based zenith DOAS and OMI. The average level of the BrO dSCD90°–80° (i.e., dSCD between 90° and 80° SZA) was 2.06 × 1014 molec·cm−2 during the period of June–November 2020. The monthly BrO dSCD90°–80° presented peaks in August and July for sunrise and sunset, respectively, and slowly increased after October. During the whole campaign period, the OClO abundance was lower than the detection limit of the instrument. This was to be expected because during that season the stratospheric temperatures were above the formation temperature of polar stratospheric clouds. Nevertheless, this finding is still of importance, because it indicates that the OClO analysis works well and is ready to be used during periods when enhanced OClO abundances can be expected. As a whole, ground-based zenith DOAS observations can serve as an effective way to measure the columns of O3 and its depleting substances over the TP. The aforementioned results are helpful in investigating stratospheric O3 chemistry over the third pole of the world.

Different Characteristics of PM2.5 Measured in Downtown and Suburban Areas of a Medium-Sized City in South Korea

Chuncheon, a medium-sized city in South Korea, frequently shows high PM2.5 concentrations despite scarce anthropogenic emission sources. To identify factors increasing PM2.5 concentrations, PM2.5 and its major chemical components were concurrently measured at two different sites, namely, downtown and suburban areas. The average PM2.5 concentrations at the two sites were similar, but the daily and monthly variations in PM2.5 and its components were significantly larger at the suburban site. NH4+ was significantly higher at the suburban site than at the downtown site, whereas organic carbon (OC) showed the opposite trend. Several PM2.5 samples showed an abrupt increase during winter at the suburban site, along with an increase in the amount of OC, NH4+, and K+, and the correlations between water-soluble OC, K+, and NH4+ were considerably strong, implying that local biomass burning in the suburban site was an important source of high PM2.5 episodes. Secondary OC (SOC) concentration was generally lower at the suburban site than at the downtown site, but its contribution to OC increased during winter with an increase in relative humidity, indicating the significance of heterogeneous SOC formation reactions at the suburban site. These results indicate that relevant local measures can be put into place to alleviate the occurrence of high PM2.5 concentration episodes even in medium-sized residential cities where medium-and long-range transport is anticipated to be significant.