Kilometre Scale Research Articles

Hit or miss: Glacial incisions of snowball Earth

AbstractEstimated at ~58 Ma in duration, the Sturtian snowball Earth (ca. 717–659 Ma) is one of the longest‐known glaciations in Earth history. Surprisingly few uncontroversial lines of evidence for glacial incisions associated with such a protracted event exist. We report here multiple lines of geological field evidence for deep but variable glacial erosion during the Sturtian glaciation. One incision, on the scale of several kilometres, represents the deepest incision documented for snowball Earth; another much more modest glacial valley, however, suggests an erosion rate similar to sluggish Quaternary glaciers. The heterogeneity in snowball glacial incisions reported here and elsewhere was likely influenced by actively extending horst‐and‐graben topography associated with the breakup of supercontinent Rodinia.

Quantification of echinoderms (Echinodermata) on Georges Bank, and the potential influence of marine protected areas on these populations

AbstractThe spatiotemporal variation of the distribution of echinoderms in the Georges Bank ecosystem was examined from 2005 to 2012. Density and abundance of representatives from echinoderm classes (brittle stars, sand dollars, sea stars, and sea urchins) were estimated using a drop camera video survey of the benthos in areas open and closed to fish trawling. The influence of closed areas on these echinoderm populations relative to a suite of key environmental and biotic factors was evaluated using Canonical Correspondence Analysis (CCA). While marine protected areas appeared to influence the distribution of sand dollars and sea stars, the distribution of brittle stars and sea urchins seemed to be defined mainly by preferred habitat conditions. According to the CCA, depth, sediment stability, temperature, predator abundance, and management area were the most important factors explaining this echinoderm assemblage. On Georges Bank, echinoderms dominate the benthic biota and are present in a variety of habitats. They can alter marine communities and are preferred prey and main predators for several commercially targeted species. The detailed information presented here (on the scale of kilometers) on abundance and spatial distribution of these populations is thus valuable towards the implementation of ecosystem‐based fisheries management.

A three-dimensional underwater sound propagation model for offshore wind farm noise prediction.

A three-dimensional underwater sound propagation model with realistic ocean environmental conditions has been created for assessing the impacts of noise from offshore wind farm construction and operation. This model utilizes an existing accurate numerical solution scheme to solve the three-dimensional Helmholtz wave equation, and it is compared and validated with acoustic transmission data between 750 and 1250 Hz collected during the development of the Block Island Wind Farm (BIWF), Rhode Island. The variability of underwater sound propagation conditions has been investigated in the BIWF area on a temporal scale of months and a spatial scale of kilometers. This study suggests that future offshore wind farm developments can exploit the seasonal variability of underwater sound propagation for mitigating noise impact by scheduling wind farm construction during periods of high acoustic transmission loss. Discussions on other applications of soundscape prediction, planning, and management are provided.

On the total entrained flow rate of artificial downwelling

Artificial downwelling potentially counteracts severe eutrophication and hypoxia in coastal regions. The entrainment that commonly occurs in the downwelling-induced plume can develop around a compensatory downward flow at a scale of kilometers, which favors below-pycnocline ventilation and thus mitigates hypoxia in bottom water. However, little discussion has been made on the entrainment of artificial downwelling. The paper focus on the total entrained (TE) flow rate that represents the magnitude of entrainment transport. Injection of a negatively buoyant jet from a round pipe into a stagnant and homogeneous ambient medium is numerically studied using a verified standard k- ε turbulence model, in which different initial pipe flow speeds, density differences and pipe radii are involved. Previous theories and experiments confirm the numerical model. An empirical formula is fitted to the simulation data to calculate the TE flow rate, which permit quantitative analysis of the capacity of ventilation for artificial downwelling. The efficiency index of ventilation (EIV) is also defined and applied to study a typical downwelling device, i.e., a tidal pump, to suggest optimal engineering parameters.

Ultrahigh‐pressure and high‐P lawsonite eclogites in Muzhaerte, Chinese western Tianshan

AbstractLawsonite eclogites are crucial to decipher material recycling along a cold geotherm into the deep Earth and orogenic geodynamics at convergent margins. However, their tectono‐metamorphic role and record especially at ultrahigh‐pressure (UHP) conditions are poorly known due to rare exposure in orogenic belts. In a ~4 km long cross‐section in Muzhaerte, China, at the western termination of the HP‐UHP metamorphic belt of western Tianshan, metabasite blocks contain omphacite and lawsonite inclusions in porphyroblastic garnet, although matrix assemblages have been significantly affected by overprinting at shallower structural levels. Two types of lawsonite eclogites occur in different parts of the section and are distinguished based on inclusion assemblages in garnet: Type 1 (UHP) with the peak equilibrium assemblage garnet+omphacite±jadeite+lawsonite+rutile+coesite±chlorite±glaucophane and Type 2 (HP) with the assemblage garnet+omphacite±diopside+lawsonite+titanite+quartz±actinolite±chlorite+glaucophane. Pristine coesite and lawsonite and their pseudomorphs in Type 1 are present in the mantle domains of zoned garnet, indicative of a coesite‐lawsonite eclogite facies. Regardless of grain size and zoning profiles, garnet with Type 1 inclusions systematically shows higher Mg and lower Ca contents than Type 2 (prp4–25grs13–24 and prp1–8grs20–45 respectively). Phase equilibria modelling indicates that the low‐Ca garnet core and mantle of Type 1 formed at UHP conditions and that there was a major difference in peak pressures (i.e., maximum return depth) between the two types (2.8–3.2 GPa at 480–590°C and 1.3–1.85 GPa at 390–500°C respectively). Scattered exposures of Type 1 lawsonite eclogite is scatteredly exposed in the north of the Muzhaerte section with a structural thickness of ~1 km, whereas Type 2 occurs throughout the rest of the section. We conclude from this regular distribution that they were derived from two contrasting units that formed along two different geothermal systems (150–200°C/GPa for the northern UHP unit and 200–300°C/GPa for the southern HP unit), with subsequent stacking of UHP and HP slices at a kilometre scale.

Impact of high‐resolution ocean–atmosphere coupling on fog formation over the North Sea

Sea‐surface temperature (SST) is a key driver for various interactions and feedbacks between components of the Earth System and can control local weather and climate. The formation of marine fog, for example, can be sensitive to small changes in SST at a scale of a few kilometres. As a contribution to understanding processes at the interface between air and sea, this article discusses results from a state‐of‐the‐art fully coupled regional atmosphere–land–ocean–wave prediction system for the UK at km scale. This study focuses on the impact of the changes in surface forcing resulting from coupling SST in the marine boundary layer and formation of summertime coastal fog over the North Sea.A study from July 2013 provided a good case to evaluate the role of SST in fog evolution. The benefit of an evolving SST in the coupled simulation is shown in capturing a warming trend in observed SST over the five‐day case study period, with a root‐mean‐square error (RMSE) against in situ observations of 1.1 K. In contrast, in uncoupled atmosphere‐only simulations, the initial‐condition SST is persisted for the duration of the case, as is more typical in current operational numerical weather prediction (NWP). In the uncoupled simulations, a cold bias develops over the modelling period and the RMSE against observed SST is 2.4 K.The impact of coupling is shown to propagate into the overlying marine boundary layer and therefore affect the formation of coastal fog. Increased heat flux from a relatively warmer sea surface in the coupled simulations led to near‐surface atmospheric instability, hampering stratus lowering and destroying the fog‐promoting inversion layer. This significantly reduced fog fractions in selected regions. The value of model coupling was assessed by comparing coupled and uncoupled simulations initialized at different times ahead of fog development.

Bulk and structural convergence at convection‐resolving scales in real‐case simulations of summertime moist convection over land

Convection‐resolving models (CRMs) are established as a solid framework to simulate moist convection in both numerical weather prediction and regional‐scale climate projections. However, capturing the different scales of the governing processes is challenging. Previous studies have shown that the size and properties of individual clouds and updraughts do not converge until horizontal grid spacings (Δx) of (100 m). We refer to this as structural convergence. On the other hand, a few recent studies have demonstrated that domain‐averaged and integrated tendencies related to a large ensemble of convective cells converge at the kilometre scale. We refer to this as bulk convergence.This study investigates both the bulk convergence of the mean diurnal cycle and spatial distribution of precipitation, clouds and convective transport, and structural convergence of cloud‐scale statistics in real‐case convection‐resolving simulations. Two nine‐day episodes of quasi‐periodic diurnal moist convection are simulated at Δx = 8.8, 4.4, 2.2, 1.1 km and 550 m over the Alps and over Central Germany to compare the results in the presence and in the absence of a mesoscale orographic forcing.Results reveal that bulk convergence is systematically achieved in both episodes for the spatial distribution of the analysed quantities. For their mean diurnal cycle, bulk convergence is generally observed in simulations over the Alps, but not over Central Germany, indicating that the presence of a mesoscale orographic forcing reduces the resolution sensitivity of the bulk flow properties. Structural convergence is confirmed to be not yet fully achieved at the kilometre scale. In particular, the size and strength of the simulated convective updraughts and the size of the smallest clouds are largely determined by Δx.

Behaviour of minor arcuate shapes hosted in curved fold-and-thrust belts: an example from the Northern Apennines (Italy)

AbstractArcuate fold-and-thrust belts have been extensively studied in the literature. Less attention, however, has been paid to the characteristics of local-scale arcuate structures, meaning 5–10 km long fold or thrust traces that display map-view curvature. Nevertheless, detailed investigation of small arcuate structures hosted in major arcs can contribute to understanding the pervasiveness of deformation mechanisms. We performed a combined geological and palaeomagnetic study on 21 sites from ac. 60 km2area in the Northern Apennines in order to analyse minor arcs at a kilometric scale. As evidenced by the geological and structural analysis performed on the 21 sites, the fold axial trend changes from N–S to NW–SE in the study area. The comparison with palaeomagnetic results shows the lack of correlation between vertical axis rotations and fold axial trends. As a consequence, the minor arcuate shapes of thrusts and related folds are interpreted as mostly primary features inherited from the geometry of the palaeomargin, represented by pre-orogenic faults, according to a context of inversion tectonics.

High‐Resolution Observations of Subsurface Fronts and Alongshore Bottom Temperature Variability Over the Inner Shelf

AbstractCirculation patterns over the inner continental shelf can be spatially complex and highly variable in time. However, few studies have examined alongshore variability over short scales of kilometers or less. To observe inner‐shelf bottom temperatures with high (5‐m) horizontal resolution, a fiber‐optic distributed temperature sensing system was deployed along a 5‐km‐long portion of the 15‐m isobath within a larger‐scale mooring array south of Martha's Vineyard, MA. Over the span of 4 months, variability at a range of scales was observed along the cable over time periods of less than a day. Notably, rapid cooling events propagated down the cable away from a tidal mixing front, showing that propagating fronts on the inner shelf can be generated locally near shallow bathymetric features in addition to remote offshore locations. Propagation velocities of observed fronts were influenced by background tidal currents in the alongshore component and show a weak correlation with theoretical gravity current speeds in the cross‐shore component. These events provide a source of cold, dense water into the inner shelf. However, differences in the magnitude and frequency of cooling events at sites separated by a few kilometers in the alongshore direction suggest that the characteristics of small‐scale variability can vary dramatically and can result in differential fluxes of water, heat, and other tracers. Thus, under stratified conditions, prolonged subsurface observations with high spatial and temporal resolution are needed to characterize the implications of three‐dimensional circulation patterns on exchange, especially in regions where the coastline and isobaths are not straight.

FULLY NONLINEAR MODELING OF NEARSHORE WAVE PROPAGATION INCLUDING THE EFFECTS OF WAVE BREAKING

Nearshore wave modeling over spatial scales of several kilometers requires balancing the fine-scale modeling of physical processes with the model’s accuracy and efficiency. In this work, a fully nonlinear potential flow model is proposed as a compromise between simplified linear, weakly nonlinear or weakly dispersive models and direct CFD approaches. The core of present approach is the use of a series representation for the velocity potential. This series contains prescribed vertical functions and allows the determination of the velocity potential in terms of unknown horizontal functions. The resulting dimensionally reduced model retains the structure of the Hamiltonian water wave system Zakharov (1968), Craig & Sulem (1993), avoiding the solution of the Laplace problem for the potential. Instead, a numerically convenient linear system of horizontal equations needs to be solved at each step in the temporal evolution. No simplifications concerning the deformation of the physical boundaries are introduced, apart from the typical requirement of a smooth, non-overturning free surface and seabed. The main limitation of this formulation is its inability to account for wave breaking. The treatment of this process is the subject of the present work. Two different techniques are implemented in the present model. Simulation results are compared to laboratory measurements for two test cases: (1) shoaling and breaking of regular waves over a barred bathymetry Beji & Battjes (1993) and (2) shoaling and breaking of regular waves on a plane beach Ting & Kirby (1994).

Simultaneous Multispacecraft Probing of Electron Phase Space Holes

AbstractWe present a series of electron holes observed simultaneously on four Magnetospheric Multiscale spacecraft in the plasma sheet boundary layer. The multispacecraft probing shows that the electron holes propagated quasi‐parallel to the local magnetic field with velocities of a few thousand kilometers per second with parallel spatial scales of a few kilometers (a few Debye lengths). The simultaneous multispacecraft probing allows analyzing the 3‐D configuration of the electron holes. We estimate the electric field gradients and charge densities associated with the electrons holes. The electric fields are fit to simple 3‐D electron hole models to estimate their perpendicular scales and demonstrate that the electron holes were generally not axially symmetric with respect to the local magnetic field. We emphasize that most of the electron holes had a complicated structure not reproduced by the simple models widely used in single‐spacecraft studies.

From depth to regional spatial genetic differentiation of Eunicella cavolini in the NW Mediterranean

Connectivity studies in the marine realm are of great importance to understand the evolutionary potential of populations in a context of growing pressures on the marine environment. Here, we investigated the effect of the local, regional, and depth spatial scale on the population genetic structure of the yellow gorgonian Eunicella cavolini, one of the most common octocoral species of the Mediterranean hard-bottom communities. This species, along with other sessile metazoans typical of coralligenous ecosystems, plays an important role in supporting biodiversity, but is also impacted by direct and indirect consequences of human activities, such as physical destruction or mortality events due to thermal anomalies. Samples were taken from 15 sites located in the Ligurian Sea (NW Mediterranean) in two adjacent regions 100 kilometres apart, i.e. from the areas of Marseille (France) and Portofino (Genoa, Italy), and were analysed using six microsatellite loci. A pattern of isolation by distance was observed at the regional as well as the local scales. Although E. cavolini showed less genetic structure than other Mediterranean octocorallian species, we observed a significant genetic differentiation between populations a few kilometres apart. A low genetic differentiation was also observed between shallow and deep populations. The occurrence of genetically differentiated populations of E. cavolini at the scale of kilometres has important consequences for the management of this species and of the associated communities.

Spatial variability in snow precipitation and accumulation in COSMO–WRF simulations and radar estimations over complex terrain

Abstract. Snow distribution in complex alpine terrain and its evolution in the future climate is important in a variety of applications including hydropower, avalanche forecasting and freshwater resources. However, it is still challenging to quantitatively forecast precipitation, especially over complex terrain where the interaction between local wind and precipitation fields strongly affects snow distribution at the mountain ridge scale. Therefore, it is essential to retrieve high-resolution information about precipitation processes over complex terrain. Here, we present very-high-resolution Weather Research and Forecasting model (WRF) simulations (COSMO–WRF), which are initialized by 2.2 km resolution Consortium for Small-scale Modeling (COSMO) analysis. To assess the ability of COSMO–WRF to represent spatial snow precipitation patterns, they are validated against operational weather radar measurements. Estimated COSMO–WRF precipitation is generally higher than estimated radar precipitation, most likely due to an overestimation of orographic precipitation enhancement in the model. The high precipitation amounts also lead to a higher spatial variability in the model compared to radar estimates. Overall, an autocorrelation and scale analysis of radar and COSMO–WRF precipitation patterns at a horizontal grid spacing of 450 m show that COSMO–WRF captures the spatial variability normalized by the domain-wide variability in precipitation patterns down to the scale of a few kilometers. However, simulated precipitation patterns systematically show a lower variability on the smallest scales of a few hundred meters compared to radar estimates. A comparison of spatial variability for different model resolutions gives evidence for an improved representation of local precipitation processes at a horizontal resolution of 50 m compared to 450 m. Additionally, differences of precipitation between 2830 m above sea level and the ground indicate that near-surface processes are active in the model.

The presence of artificial water points structures an arid-zone avian community over small spatial scales

Water plays a key role in avian thermoregulation, especially when environmental temperatures approach or exceed body temperature. Birds living in arid environments need to either be adapted to life with unreliable access to water, or engage in large-scale movements to access water. This study asked whether species richness and the distribution of bird species in the Kalahari landscape across scales of kilometres is predicted by the availability of open water sources. We conducted point count surveys for birds and modelled these as a function of habitat variables and distance to the nearest water source. We recorded 52 species during our point counts. Despite much variation in species richness scores at each point, species richness decreased with increasing distance from water. Granivorous birds were most dependent on water and showed higher probability of occurrence closer to water. Vegetation height impacted detectability for seven species, negatively for four and significantly positively for two. The provisioning of artificial water in the Kalahari is likely facilitating the presence and abundance of some bird species, notably seed eaters. Communities of birds will likely change if water points are closed or water becomes scarcer under climate change, which could well alter the ecosystem functioning of these regions.

Fine-scale geographic patterns of gene flow and reproductive character displacement in Drosophila subquinaria and Drosophila recens.

When two species are incompletely isolated, strengthening premating isolation barriers in response to the production of low fitness hybrids may complete the speciation process. Here, we use the sister species Drosophila subquinaria and Drosophila recens to study the conditions under which this reinforcement of species boundaries occurs in natural populations. We first extend the region of known sympatry between these species, and then we conduct a fine-scale geographic survey of mate discrimination coupled with estimates of gene flow within and admixture between species. Within D.subquinaria, reinforcement is extremely effective: we find variation in mate discrimination both against D.recens males and against conspecific allopatric males on the scale of a few kilometres and in the face of gene flow both from conspecific populations and introgression from D.recens. In D.recens, we do not find evidence for increased mate discrimination in sympatry, even where D.recens is rare, consistent with substantial gene flow throughout the species' range. Finally, we find that introgression between species is asymmetric, with more from D.recens into D.subquinaria than vice versa. Within each species, admixture is highest in the geographic region where it is rare relative to the other species, suggesting that when hybrids are produced they are of low fitness. In sum, reinforcement within D.subquinaria is effective at maintaining species boundaries, but even when reinforcing selection is strong it may not always result in a pattern of strong reproductive character displacement due to variation in the frequency of hybridization and gene flow from neighbouring populations.

Evaluating tools for the spatial management of fisheries

Abstract The ability to define the spatial dynamics of fish stocks is critical to fisheries management. Combating illegal, unreported and unregulated fishing and the regulation of area‐based management through physical patrols and port side controls are growing areas of management attention. Augmenting the existing approaches to fisheries management with forensic techniques has the potential to increase compliance and enforcement success rates. We tested the accuracy of three techniques (genotyping, otolith microchemistry and morphometrics) that can be used to identify geographic origin. We used fish caught from three fishing grounds, separated by a minimum of 5 km and a maximum of 60 km, to test the accuracy of these approaches at relatively small spatial scales. Using nearest‐neighbour analyses, morphometric analysis was the most accurate (79.5%) in assigning individual fish to their fishing ground of origin. Neither otolith microchemistry (54.0%) or genetic analyses (52.4%) had sufficient accuracy at the spatial scales we examined. Synthesis and applications. The combination of accuracy and minimal resource requirements make morphometric analysis a promising tool for assessing compliance with area‐based fishing restrictions at the scale of kilometres. Furthermore, this approach has promising application, in small‐scale fisheries through to community‐based management approaches where technical and financial resources are limited.

Observations of a Submesoscale Cyclonic Filament in the Marginal Ice Zone

AbstractSubmesoscale flows are energetic motions on scales of several kilometers that may lead to substantial vertical motions. Here we present satellite and ship radar as well as underway conductivity‐temperature‐depth and Acoustic Doppler Current Profiler observations of a cyclonic submesoscale filament in the marginal ice zone of Fram Strait. The filament created a 500‐m thin and 50‐km long sea ice streak and extends to >250‐m depth with a negative/positive density anomaly within/below the halocline. The frontal jets of 0.5 m/s are in turbulent thermal wind balance while the ageostrophic secondary circulation in places appears to subduct Atlantic Water at >50 m/day. Our study reveals the submesoscale dynamics related to sea ice shapes that can be sensed remotely and shows how submesoscale dynamics contribute to shaping the marginal ice zone. It also demonstrates the co‐occurrence and mixing of water masses over short horizontal scales, which has implications for ocean and sea ice models and understanding of patch formation of planktonic organisms.

SAR Mode Altimetry Observations of Internal Solitary Waves in the Tropical Ocean Part 1: Case Studies

It is well known that internal waves (IWs) of tidal frequency (i.e., internal tides) are successfully detected in sea surface height (SSH) by satellite altimetry. Shorter period internal solitary waves (ISWs), whose periods (and spatial scales) are an order of magnitude smaller than tidal internal waves, have been generally assumed too small to be detected with conventional altimeters. This is because conventional (pulse-limited) radar altimeter footprints are somewhat larger than or of similar size, at best, as the typical wavelengths of the ISWs. Here we demonstrate that the synthetic aperture radar altimeter (SRAL) on board the Sentinel-3A can detect short-period ISWs. A variety of signatures owing to the surface manifestations of the ISWs are apparent in the SRAL Level-2 products over the ocean. These signatures are identified in several geophysical parameters, such as radar backscatter (sigma0), sea level anomaly (SLA), and significant wave height (SWH). Radar backscatter is the primary parameter in which ISWs can be identified owing to the measurable sea surface roughness perturbations in the along-track sharpened SRAL footprint. The SRAL footprint is sufficiently small to capture radar power fluctuations over successive wave crests and troughs, which produce rough and slick surface patterns arrayed in parallel bands with scales of a few kilometers. The ISW signatures are unambiguously identified in the SRAL because of the exact synergy with OLCI (Ocean Land Colour Imager) images, which in cloud-free conditions allow clear identification of the ISWs in the sunglint OLCI images. We show that both sigma0 and SLA yield realistic estimates for routine observation of ISWs with the SRAL, which is a significant improvement from previous observations recently reported for conventional pulse-limited altimeters (Jason-2). Several case studies of ISW signatures are interpreted in light of our knowledge of radar backscatter in the internal wave field. An analysis is presented for the tropical Atlantic Ocean off the Amazon shelf to infer the frequency of the phenomena, being consistent with previous satellite observations in the study region.

A Multiplicative Cascade Model for High‐Resolution Space‐Time Downscaling of Rainfall

AbstractDistributions of rainfall with the time and space resolutions of minutes and kilometers, respectively, are often needed to drive the hydrological models used in a range of engineering, environmental, and urban design applications. The work described here is the first step in constructing a model capable of downscaling rainfall to scales of minutes and kilometers from time and space resolutions of several hours and a hundred kilometers. A multiplicative random cascade model known as the Short‐Term Ensemble Prediction System is run with parameters from the radar observations at Melbourne (Australia). The orographic effects are added through multiplicative correction factor after the model is run. In the first set of model calculations, 112 significant rain events over Melbourne are simulated 100 times. Because of the stochastic nature of the cascade model, the simulations represent 100 possible realizations of the same rain event. The cascade model produces realistic spatial and temporal patterns of rainfall at 6 min and 1 km resolution (the resolution of the radar data), the statistical properties of which are in close agreement with observation. In the second set of calculations, the cascade model is run continuously for all days from January 2008 to August 2015 and the rainfall accumulations are compared at 12 locations in the greater Melbourne area. The statistical properties of the observations lie with envelope of the 100 ensemble members. The model successfully reproduces the frequency distribution of the 6 min rainfall intensities, storm durations, interarrival times, and autocorrelation function.

SeNorge2 daily precipitation, an observational gridded dataset over Norway from 1957 to the present day

Abstract. The conventional climate gridded datasets based on observations only are widely used in atmospheric sciences; our focus in this paper is on climate and hydrology. On the Norwegian mainland, seNorge2 provides high-resolution fields of daily total precipitation for applications requiring long-term datasets at regional or national level, where the challenge is to simulate small-scale processes often taking place in complex terrain. The dataset constitutes a valuable meteorological input for snow and hydrological simulations; it is updated daily and presented on a high-resolution grid (1 km of grid spacing). The climate archive goes back to 1957. The spatial interpolation scheme builds upon classical methods, such as optimal interpolation and successive-correction schemes. An original approach based on (spatial) scale-separation concepts has been implemented which uses geographical coordinates and elevation as complementary information in the interpolation. seNorge2 daily precipitation fields represent local precipitation features at spatial scales of a few kilometers, depending on the station network density. In the surroundings of a station or in dense station areas, the predictions are quite accurate even for intense precipitation. For most of the grid points, the performances are comparable to or better than a state-of-the-art pan-European dataset (E-OBS), because of the higher effective resolution of seNorge2. However, in very data-sparse areas, such as in the mountainous region of southern Norway, seNorge2 underestimates precipitation because it does not make use of enough geographical information to compensate for the lack of observations. The evaluation of seNorge2 as the meteorological forcing for the seNorge snow model and the DDD (Distance Distribution Dynamics) rainfall–runoff model shows that both models have been able to make profitable use of seNorge2, partly because of the automatic calibration procedure they incorporate for precipitation. The seNorge2 dataset 1957–2015 is available at https://doi.org/10.5281/zenodo.845733. Daily updates from 2015 onwards are available at http://thredds.met.no/thredds/catalog/metusers/senorge2/seNorge2/provisional_archive/PREC1d/gridded_dataset/catalog.html.