Satellite monitoring of ammonia: from point sources to long-term trends

IASI satellite ammonia (NH3) measurements are used to identify, categorise and quantify world's NH3 emission hotspots. In particular, applying spatial oversampling and supersampling techniques on more than 10 years of IASI measurements, we are able to track-down more than 500 localized point sources of agricultural, industrial (fertilizer, coking, soda ash, geothermal and explosives industries), urban and natural origin. We present an on-line global NH3 point sources catalogue, consisting of an interactive global map, visualizing the distribution, type and time evolution of the different point sources (http://www.ulb.ac.be/cpm/NH3-IASI.html). Calculated satellite-based emissions of NH3 suggest a drastic underestimation of point sources in bottom-up inventories, especially those of industrial emitters. Temporal analysis revealed rapid shifts in anthropogenic activities, such as the opening or closure of industrial plants. These results demonstrate that using NH3 satellite data will be hugely beneficial for improving bottom-up emission inventories.A recently obtained homogeneous data record of NH3 total columns from IASI (ANNI-NH3-v3R) is also used to derive trends over the last decade. We apply a bootstrap resampling method to determine the trends and to assess whether the calculated values are significant or not. We obtain the first global distribution (0.5&#176;&#215;0.5&#176;) of atmospheric NH3 trends based on 11 years (2008-2018) of IASI/Metop-A observations. Distinct temporal patterns are extracted and are analysed in light of anthropogenic activities and biomass burning events. National absolute and relative trends are also calculated and discussed.

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Geochemical and statistical evaluation of groundwater in the Thamirabarani river basin, south India

10.21203/rs.3.rs-163816/v1 ◽

2021 ◽

Author(s):

Gajendran Chellaiah ◽

Basker ◽

Hima Pravin ◽

Suneel Kumar Joshi ◽

Sneha Gautam

Keyword(s):

River Basin ◽

Tamil Nadu ◽

Statistical Evaluation ◽

Anthropogenic Activities ◽

Monsoon Season ◽

Principal Component ◽

Chloride Ion ◽

Temporal Analysis ◽

Point Sources ◽

International Standards

Abstract In the present study, an attempt has been made to develop the dictate metrics using a multi-proxy approach, i.e., spatial-temporal analysis, statistical evaluation, and hydrogeochemical analysis for 45 water samples located in the Thamirabarani river basin in Tamil Nadu, India. In order to evaluate the aptness of developed metrics for agriculture and domestic needs, eleven years dataset was analyzed and compared with national and international standards. Monitoring and analysis results revealed that the concentration of calcium and chloride ion was on the higher side in all the selected locations. These higher values may be attributed to the regional point sources such as untreated water disposal and off-peak sources such as agriculture practices. The principal component analysis resulted in 84.2% of the total variance in the post-monsoon season dataset. The major analyzed cations and anions were observed in the following order: Na+> Ca2+> Mg2+> K+ and Cl−> HCO3−> SO42−> NO3−, respectively. Overall, this study revealed that the studied area's groundwater quality was significantly affected by the high salinity in the region, probably due to anthropogenic activities and unprotected river sites.

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ANALYSIS OF THE SHORELINE POSITION EXTRACTED FROM LANDSAT TM AND ETM+ IMAGERY

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprsarchives-xl-7-w3-991-2015 ◽

2015 ◽

Vol XL-7/W3 ◽

pp. 991-998 ◽

Cited By ~ 5

Author(s):

E. Sánchez-García ◽

J. E. Pardo-Pascual ◽

A. Balaguer-Beser ◽

J. Almonacid-Caballer

Keyword(s):

Statistical Tests ◽

Landsat Imagery ◽

Temporal Analysis ◽

Long Term Trends ◽

Annual Means ◽

Run Up ◽

Incident Waves ◽

Intrinsic Error ◽

Average Position

A statistical analysis of the results obtained by the tool SELI (Shoreline Extraction from Landsat Imagery) is made in order to characterise the medium and long term period changes occurring on beaches. The analysis is based on the hypothesis that intraannual shifts of coastline positions hover around an average position, which would be significant when trying to set these medium and long term trends. Fluctuations around this average are understood as the effect of short-term changes -variations related to sea level, wave run-up, and the immediate morphological beach profile settings of the incident waves- whilst the alterations of the average position will obey changes relating to the global sedimentary harmony of the analysed beach segment. The goal of this study is to assess the validity of extracted Landsat shorelines knowing whether the intrinsic error could alter the position of the computed mean annual shoreline or if it is balanced out between the successive averaged images. Two periods are stablished for the temporal analysis in the area according to the availability of other data taken from high precision sources. Statistical tests performed to compare samples (Landsat versus high accuracy) indicate that the two sources of data provide similar information regarding annual means; coastal behaviour and dynamics, thereby verifying Landsat shorelines as useful data for evolutionary studies.

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Drivers of long-term trends and seasonal changes in total phosphorus loads to a mesotrophic lake in the west of Ireland

Marine and Freshwater Research ◽

10.1071/mf12166 ◽

2013 ◽

Vol 64 (5) ◽

pp. 413 ◽

Cited By ~ 3

Author(s):

Eleanor Jennings ◽

Norman Allott ◽

David Lenihan ◽

Bill Quirke ◽

David Taylor ◽

...

Keyword(s):

Significant Contribution ◽

Wastewater Treatment Plants ◽

Surface Water Quality ◽

Point Sources ◽

Residence Times ◽

South West ◽

Long Term Trends ◽

Phosphorus Loads ◽

Pollution Impacts

Excess phosphorus (P) loading is a major cause of deterioration in surface water quality. In Ireland, regulation has focussed on control of P losses from agriculture and wastewater treatment plants (WWTPs): the two main sources of excess P. Hindcast modelling for Lough Leane, south-west Ireland, indicated that, while the only municipal (point) source contributed up to 41% of the annual TP loading until the mid 1980s, over 90% of the TP load was from diffuse sources following upgrading of the WWTP. Field data from 2000–2006 confirmed that most of the TP load came from agriculture, with 73% being exported between September and February, generally the wettest months in the region. However, the WWTP contributed up to 60% of daily loads during summer. Short lake residence times (two to four months) between October and February indicated that external loadings during these months were unlikely to make a significant contribution to summer phytoplankton growth in the lake. In contrast, the potential effects of point sources during low flows were maximised by longer residence times between April and September. The results highlight the importance to aquatic pollution impacts of, and therefore the need for regulatory responses to respect, seasonal variations in loading and residence time.

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