Morning ritual - Evaporation

Unfortunately in most cases we can see water change from liquid to vapor. However, morgenstund hat Gold im Mund, the early bird catches the worm or a hydrologist catches evaporation check the video with a cup of tea evaporating. Check the thin layer of condensation (whitish) on top the tea blown away ...

Have a nice day :)

... +1 <:D update: 24.01.17 | Spatial variability in the isotopic composition of rainfall

Abstract

Isotope hydrograph separation (IHS) is a valuable tool to study runoff generation processes. To perform an IHS, samples of baseflow (pre-event water) and streamflow are taken at the catchment outlet. For rainfall (event water) either a bulk sample is collected or it is sampled sequentially during the event. For small headwater catchment studies, event water samples are usually taken at only one sampling location in or near the catchment because the spatial variability in the isotopic composition of rainfall is assumed to be small. However, few studies have tested this assumption. In this study, we investigated the spatiotemporal variability in the isotopic composition of rainfall and its effects on IHS results using detailed measurements from a small pre-alpine headwater catchment in Switzerland. Rainfall was sampled sequentially at eight locations across the 4.3 km2 Zwäckentobel catchment and stream water was collected in three subcatchments (0.15, 0.23, and 0.70 km2) during ten events. The spatial variability in rainfall amount, average and maximum rainfall intensity and the isotopic composition of rainfall was different for each event. There was no significant relation between the isotopic composition of rainfall and total rainfall amount, rainfall intensity or elevation. For eight of the ten studied events the temporal variability in the isotopic composition of rainfall was larger than the spatial variability in the rainfall isotopic composition. The isotope hydrograph separation results, using only one rain sampler, varied considerably depending on which rain sampler was used to represent the isotopic composition of event water. The calculated minimum pre-event water contributions differed up to 60%. The differences were particularly large for events with a large spatial variability in the isotopic composition of rainfall and a small difference between the event and pre-event water isotopic composition. Our results demonstrate that even in small catchments the spatial variability in the rainfall isotopic composition can be significant and has to be considered for IHS studies. Using data from only one rain sampler can result in significant errors in the estimated pre-event water contributions to streamflow.

Automatic samplers and mountaineers ...

To use some sort of stimulating substances to increase the performance seems a wide spread phenomenon reading newspapers:

• …
• Cyclist
• Students
• Researchers (in best case coffee)

Now reading that even mountaineers (and those who want to be), can be added to the list. To get up to the higher elevations, beside O2 (most likely enriched 18O compared to surrounding composition), a quite a long list of stuff is used. In the NZZ article on drugs and mountaineering a reference was made to a nice study in plos. The study of Rohbach etal Plos 2016 used a cool sampling setup to monitor and prove one or several drugs in male "discharge", suggesting frequent drug use among climbers ascending Mont Blanc!!! Only a shame the team of Rohbach didn't use a lab in the field for continuous measurements and forgot to analyze the stable isotope composition of the water.

The automatic samplers collecting pristine streamwater e.g. Fischer et al. HR 2017 or Fischer et al. JoH 2017 are lucky to be out in a clean and fresh environment. Unfortunate are the automatic samplers which are used to sample sewerage systems e.g. Ort et al.  EST 2010  to investigate Sampling for Pharmaceuticals and Personal Care Products (PPCPs) and Illicit Drugs in Wastewater Systems or the ingenious sampling setup of Rohbach check: 

Sampling setup of Rohbach et al. Plos 2016 using an automatic sampler. Poor PhD student who has to empty the sampler. 

Next time one (man/women) is on the toilet and hears a strange peristaltic pump type noise... most likely some body is investigating your coffee or ... consumption.

Ref:

Fischer, B. M. C., Stähli, M., Seibert, J., Stahli, M., & Seibert, J. (2017). Pre-event water contributions to runoff events of different magnitude in pre-alpine headwaters. Hydrology Research, nh2016176. https://doi.org/10.2166/nh.2016.176

Fischer, B. M. C., van Meerveld, H. J., & Seibert, J. (2017). Spatial variability in the isotopic composition of rainfall in a small headwater catchment and its effect on hydrograph separation. Journal of Hydrology.

Ort, C., Lawrence, M. G., Reungoat, J., & Mueller, J. F. (2010). Sampling for PPCPs in wastewater systems: comparison of different sampling modes and optimization strategies. Environ. Sci. Technol., 44(16), 6289–6296. https://doi.org/10.1021/es100778d

Robach P, Trebes G, Lasne F, Buisson C, Méchin N, Mazzarino M, et al. (2016) Drug Use on Mont Blanc: A Study Using Automated Urine Collection. PLoS ONE 11(6): e0156786. doi:10.1371/journal.pone.0156786

Alptal samplers:

Automatic water sampler in a pristine pre-alpine headwater catchment-WS07 (Fischer et al. HR2017)  

Although pristine waters, in case a colleague is using uranine as a fluro tracer to measure discharge the samples can get a bit yellow :S  

Kaleidoscope...

Kaleidoscope...  














... cross your fingers!