Supplementary material to "Seasonal Variability in In-situ Supraglacial Streamflow and Drivers in Southwest Greenland in 2016"

Abstract. Greenland ice sheet surface runoff is evacuated through supraglacial stream networks, which influence surface mass balance as well as ice dynamics. However, in-situ observations of meltwater discharge through these stream networks are rare. In this study, we present 46 discharge measurements and continuous water level measurements for 62 days spanning 13 June to 13 August 2016 for a 0.6 km2 supraglacial stream catchment in southwest Greenland. The result is an unprecedented long record of supraglacial discharge capturing both diurnal and seasonal variability. By comparing in situ hydraulic geometry parameters with previous studies, we find that significant heterogeneity exists such that estimating stream discharge using these parameters over ungauged supraglacial catchments could lead to substantial errors. A comparison of surface energy fluxes to stream discharge reveals shortwave radiation as the primary driver of melting (78 % of melt energy). However, during high melt episodes, the shortwave only contributes to 50 % of melt energy. Instead, the relative contribution of longwave radiation, sensible and latent heat fluxes to overall melt increases by 16.5 %, 4 %, and 7 % respectively. Our data also show a seasonal variation in the timing of daily maximum discharge during clear sky days, shifting from 16:00 local time (i.e., 2.75 hours after solar noon) in late June to 14:00 in late July, then rapidly returns to 16:00 in early August coincident with an abrupt drop in air temperature. These changes in peak daily flow timing can be attributed to a changing effective catchment area, resulting in a smaller stream network supplying water to the outlet at the end of the season throughout the melt season. Further work is needed to uncover how widespread rapid shift in the timing of peak discharge is across Greenland supraglacial streams, and thus their potential impact on meltwater delivery to the subglacial system and ice dynamics.

Download Full-text

Sea Surface Salinity Seasonal Variability in the Tropics from Satellites, Gridded in situ Products and Mooring Observations

10.1002/essoar.10505049.2 ◽

2020 ◽

Author(s):

Frederick Bingham ◽

Frederick M Bingham ◽

Susannah Brodnitz ◽

Lisan Yu

Keyword(s):

Seasonal Variability ◽

Sea Surface ◽

Sea Surface Salinity ◽

Surface Salinity ◽

The Tropics

Download Full-text

Geochemical evaluation of the in-situ regolith of Madengi hills of Dodoma, Tanzania. Implication on bedrock mapping and delineating gold mineralization target

Geochemistry Exploration Environment Analysis ◽

10.1144/geochem2021-074 ◽

2021 ◽

pp. geochem2021-074

Author(s):

Godson Godfray

Keyword(s):

Gold Mineralization ◽

Early Stage ◽

Shear Zones ◽

Soil Geochemistry ◽

Residual Soils ◽

Content Type ◽

Geochemical Evaluation ◽

Supplementary Material ◽

Pathfinder Elements

Successful gold exploration projects depend on a piece of clear information on the association between gold, trace elements, and mineralization controlling factors. The use of soil geochemistry has been an important tool in pinpointing exploration targets during the early stage of exploration. This study aimed to establish the gold distribution, the elemental association between gold and its pathfinder elements such as Cu, Zn, Ag, Ni, Co, Mn, Fe, Cd, V, Cr, Ti, Sc, In, and Se and identify lithologies contributing to the overlying residual soils. From cluster analysis, a high similarity level of 53.93% has been shown with Ag, Cd, and Se at a distance level of 0.92. Au and Se have a similarity level of 65.87% and a distance level of 0.68, hence is proposed to be the most promising pathfinder element. PCA, FA, and the Pearson's correlation matrix of transformed data of V, Cu, Ni, Fe, Mn, Cr, and Co and a stronger correlation between Pb and U, Th, Na, K, Sn, Y, Ta and Be shows that source gold mineralization might be associated with both hornblende gneisses interlayered with quartzite, tonalite, and tonalitic orthogneiss. From the contour map and gridded map of Au and its pathfinder elements, it has been noted that their anomalies and target generated are localized in the Northern part of the area. The targets trend ESE to WNW nearly parallel to the shear zones as a controlling factor of Au mineralization emplacement.Supplementary material:https://doi.org/10.6084/m9.figshare.c.5721965

Download Full-text