Reaction rates of radiatively and chemically active trace species are influenced by the mobility of air contained within the snowpack. By measuring wind speed and the evolution of a tracer gas with in situ sensors over a 1 m horizontal grid, we found that inhomogeneities in a single snow layer enhanced air movement unevenly as wind speed increased. This result suggests small-scale variability in reaction rates that increases with wind speed and variability in snow permeability.

Intrinsic permeability of snow is an important parameter that regulates snow–atmosphere exchange. Current permeability measurements require specialized equipment for acquisition in the field and have increased variability with increasing snow heterogeneity. To facilitate a field-based, volume-averaged measure of permeability, we designed and assembled an acoustic permeameter. When using reticulated foam samples of known permeability, the mean relative error from known values was less than 20 %.

Fibre optic distributed temperature sensing allows one to measure temperature patterns along a fibre optic cable with resolutions down to 25 cm. In geosciences, we sometimes wrap the cable to a coil to measure temperature at even smaller scales. We show that coils with narrow bends affect the measured temperatures. This also holds for the object to which the coil is attached, when heated by solar radiation. We therefore recommend the necessity to carefully design such distributed temperature probes.

The monitoring and measurement of water flow in groundwater wells allows us to understand how aquifers transmit water. In this paper we develop a simple method, which we call T-POT, that allows flows to be estimated by tracking the movement of a small parcel of warmed water. The parcel is tracked using fibre optic temperature sensing - a technology that allows detailed measurements of temperature, and therefore flow using the T-POT method, to be made in the well.

We present a new instrument for measuring surface runoff rates ranging from very low (~0.05L min-1) to high (300L min-1, with much higher rates possible depending on the device configuration). The device is economical, simple, rugged, accurate and requires little maintenance (the system is self-emptying and contains no moving parts). We have successfully used this instrument in long-term monitoring studies and expect that it will appeal to other scientists studying runoff processes.