A high space–time resolution dataset linking meteorological forcing and hydro-sedimentary response in a mesoscale Mediterranean catchment (Auzon) of the Ardèche region, France

Abstract

Abstract.A comprehensive hydrometeorological dataset is presented spanning the period 1 January 2011-31 December 2014 to improve the understanding of the hydrological processes leading to flash floods and the relation between rainfall, runoff, erosion and sediment transport in a mesoscale catchment (Auzon, 116 km 2 ) of the Mediterranean region. Badlands are present in the Auzon catchment and well connected to high-gradient channels of bedrock rivers which promotes the transfer of suspended solids downstream. The number of observed variables, the various sensors involved (both in situ and remote) and the space-time resolution (∼ km 2 , ∼ min) of this comprehensive dataset make it a unique contribution to research communities focused on hydrometeorology, surface hydrology and erosion. Given that rainfall is highly variable in space and time in this region, the observation system enables assessment of the hydrological response to rainfall fields. Indeed, (i) rainfall data are provided by rain gauges (both a research network of 21 rain gauges with a 5 min time step and an operational network of 10 rain gauges with a 5 min or 1 h time step), S-band Doppler dual-polarization radars (1 km 2 , 5 min resolution), disdrometers (16 sensors working at 30 s or 1 min time step) and Micro Rain Radars (5 sensors, 100 m height resolution). Additionally, during the special observation period (SOP-1) of the HyMeX (Hydrological Cycle in the Mediterranean Experiment) project, two X-band radars provided precipitation measurements atPublished by Copernicus Publications. 222G. Nord et al.: High-resolution hydrometeorological data in a mesoscale Mediterranean catchment very fine spatial and temporal scales (1 ha, 5 min). (ii) Other meteorological data are taken from the operational surface weather observation stations of Météo-France (including 2 m air temperature, atmospheric pressure, 2 m relative humidity, 10 m wind speed and direction, global radiation) at the hourly time resolution (six stations in the region of interest). (iii) The monitoring of surface hydrology and suspended sediment is multi-scale and based on nested catchments. Three hydrometric stations estimate water discharge at a 2-10 min time resolution. Two of these stations also measure additional physico-chemical variables (turbidity, temperature, conductivity) and water samples are collected automatically during floods, allowing further geochemical characterization of water and suspended solids. Two experimental plots monitor overland flow and erosion at 1 min time resolution on a hillslope with vineyard. A network of 11 sensors installed in the intermittent hydrographic network continuously measures water level and water temperature in headwater subcatchments (from 0.17 to 116 km 2 ) at a time resolution of 2-5 min. A network of soil moisture sensors enables the continuous measurement of soil volumetric water content at 20 min time resolution at 9 sites. Additionally, concomitant observations (soil moisture measurements and stream gauging) were performed during floo...

Retrieval of the raindrop size distribution from polarimetric radar data using double-moment normalisation

“…HyMeX MXPol, MRR, and Parsivel data are available through the HyMeX database at http://www.hymex.org, and DOIs for individual data sets are listed in Nord et al (2017). Weather station data, Payerne radar data, and Payerne Parsivel data are publicly available upon request from EPFL-LTE.…”

Drop Size Distribution Climatology in Cévennes-Vivarais Region, France

“…This network was initiated in 2004 (Alès station, [30]) and was densified during the HyMeX project, whose special observation period (SOP) took place in 2012 [33]. During this SOP, the network contained up to 25 stations, half of which were grouped on a dense network called "Hpiconet" [36] and was centred on the Auzon watershed [37]. For this study, covering the period 2012-2016, six stations were selected, according to two transects, going from the mountain to a hilly area, via a transition zone at the foot of the first mountains.…”

How does initial soil moisture influence the hydrological response? A case study from southern France

“…Both catchments can be clearly divided into two distinct geologies: the northern part is constituted by the Coiron basaltic 20 plateau that is bounded by a steep cliff of basaltic columns in the south, whereas the southern part of both catchments is a landscape of piedmont hills underlain by sedimentary limestone lithology (Nord et al, 2017). The basaltic plateau covers 51 % of the Claduègne catchment whereas its fraction of the Gazel catchment is only 23 %.…”

“…The lack of high-resolution data as well as the variety of catchment characteristics that influence 25 the occurrence of flash floods and the high degree of non-linearity in the hydrological response of catchments hinder the predictability of flash floods (Braud et al, 2014). This has motivated the installation of several measurement networks in first-order catchments especially in the USA and Australia and -at the mesoscale and in a Mediterranean context -the FloodScale project in the Cévennes-Vivarais region (Braud et al, 2014, Nord et al, 2017.…”