Eddies in motion : visualizing boundary-layer turbulence above an open boreal peatland using UAS thermal videos

High-resolution thermal infrared (TIR) imaging is opening up new vistas in biosphere-atmosphere heat exchange studies. The rapidly developing unmanned aerial systems (UASs) and specially designed cameras offer opportunities for TIR survey with increasingly high resolution, reduced geometric and radiometric noise, and prolonged flight times. A state-of-the-art science platform is assembled using a Matrice 210 V2 drone equipped with a Zenmuse XT2 thermal camera and deployed over a pristine boreal peatland with the aim of testing its performance in a heterogeneous sedgefen ecosystem. The study utilizes the capability of the UAS platform to hover for prolonged times (about 20 min) at a height of 500ma.g.l. while recording high frame rate (30 Hz) TIR videos of an area of ca. 430 x 340 m. A methodology is developed to derive thermal signatures of near-ground coherent turbulent structures impinging on the land surface, surface temperature spectra, and heat fluxes from the retrieved videos. The size, orientation, and movement of the coherent structures are computed from the surface temperature maps, and their dependency on atmospheric conditions is examined. A range of spectral and wavelet-based approaches are used to infer the properties of the dominant turbulent scene structures. A ground-based eddy-covariance system and an in situ meteorological setup are used for reference.Peer reviewe

Sea ice and related data sets from the Baltic Sea AICSEX : Metadata report

Julkaisu sisältää myös kolme muuta artikkelia: Kimmo K. Kahma, Heidi Pettersson & Laura Tuomi: Scatter diagram wave statistics from the northern Baltic Sea Matti Perttilä (Editor): Assessment — State of the Gulf of Finland in 2002 Tapani Stipa, Morten Skogen, Ian Sehested Hansen, Anders Eriksen, Inga Hense, Anniina Kiiltomäki, Henrik Soiland & Antti Westerlund: Short-term effects of nutrient reductions in the North Sea and the Baltic Sea as seen by an ensemble of numerical model

Metsätalouden vesistökuormituksen seuranta- ja raportointiohjelma

Metsätalouden vesistökuormituksen seurantaverkon muodostavat luonnon taustakuormituksen ja normaalin metsätaloustoiminnan aiheuttaman kuormituksen seurantaan perustetut latvavaluma alueet. Verkon avulla voidaan tuottaa valtakunnalliset sekä vesienhoitoalue- ja jokivaluma-aluekohtaiset arviot metsätalouden aiheuttamasta kuormituksesta ja seurata esim. muuttuvista ilmasto-oloista tai metsätalouden intensiteetin muutoksista aiheutuvia trendejä. Seurantaverkko perustettiin vuonna 2014 ja seurantaa toteutetaan yhteistyössä Luonnonvarakeskuksen, Suomen ympäristökeskuksen (SYKE), Metsähallituksen, Suomen Metsäkeskusten, ELY-keskusten ja Tapio Oy:n kanssa. Näytteenottoa ja laboratorioanalyysejä on ulkoistettu yksityisille toimijoille. Tämä raportti kuvaa seurantaverkkoon kuuluvat valuma-alueet, aineiston keruumenetelmät ja tulosten laskennan.201

NutSpaFHy : A Distributed Nutrient Balance Model to Predict Nutrient Export from Managed Boreal Headwater Catchments

Responsible forest management requires accounting for adverse environmental effects, such as increased nutrient export to water courses. We constructed a spatially-distributed nutrient balance model NutSpaFHy that extends the hydrological model SpaFHy by introducing a grid-based nutrient balance sub-model and a conceptual solute transport routine to approximate total nitrogen (N) and phosphorus (P) export to streams. NutSpaFHy uses openly-available Multi-Source National Forest Inventory data, soil maps, topographic databases, location of water bodies, and meteorological variables as input, and computes nutrient processes in monthly time-steps. NutSpaFHy contains two calibrated parameters both for N and P, which were optimized against measured N and P concentrations in runoff from twelve forested catchments distributed across Finland. NutSpaFHy was independently tested against six catchments. The model produced realistic nutrient exports. For one catchment, we simulated 25 scenarios, where clear-cuts were located differently with respect to distance to water body, location on mineral or peat soil, and on sites with different fertility. Results indicate that NutSpaFHy can be used to identify current and future nutrient export hot spots, allowing comparison of logging scenarios with variable harvesting area, location and harvest techniques, and to identify acceptable scenarios that preserve the wood supply whilst maintaining acceptable level of nutrient export

Kunnostusojituksen tarpeellisuuden arviointi mallinnuksen keinoin

201

Combined use of satellite image analysis, land-use statistics, and land-use-specific export coefficients to predict nutrients in drained peatland catchment

Highlights • Nutrient and SS estimations were predicted by comparing different approaches. • Peatland drainage strongly affected TN, TP, and SS loads and concentrations. • Uncertainty in estimates captured 29–90% of measured TN, TP, and SS values. • The uncertainty in export coefficients decreased with catchment size.Maintaining and improving surface water quality requires knowledge of nutrient and sediment loads due to past and future land-use practices, but historical data on land cover and its changes are often lacking. In this study, we tested whether land-use-specific export coefficients can be used together with satellite images (Landsat) and/or regional land-use statistics to estimate riverine nutrient loads and concentrations of total nitrogen (TN), total phosphorus (TP), and suspended solids (SS). The study area, Simojoki (3160 km2) in northern Finland, has been intensively drained for peatland forestry since the 1960s. We used different approaches at multiple sub-catchment scales to simulate TN, TP, and SS export in the Simojoki catchment. The uncertainty in estimates based on specific export coefficients was quantified based on historical land-use changes (derived from Landsat data), and an uncertainty boundary was established for each land-use. The uncertainty boundary captured at least 60% of measured values of TN, TP, and SS loads or concentrations. However, the uncertainty in estimates compared with measured values ranged from 7% to 20% for TN, 0% to 18% for TP, and 13% to 43% for SS for different catchments. Some discrepancy between predicted and measured loads and concentrations was expected, as the method did not account for inter-annual variability in hydrological conditions or river processes. However, combining historical land-use change estimates with simple export coefficients can be a practical approach for evaluating the influence on water quality of historical land-use changes such as peatland drainage for forest establishment

Metsätalouden vesistökuormitus : nykykäsitys ja tulevaisuuden menetelmäkehitys

Peer reviewe

Modelling spatio-temporal soil moisture dynamics in mountain tundra

Abstract Soil moisture has a fundamental influence on the processes and functions of tundra ecosystems. Yet, the local dynamics of soil moisture are often ignored, due to the lack of fine resolution, spatially extensive data. In this study, we modelled soil moisture with two mechanistic models, SpaFHy (a catchment-scale hydrological model) and JSBACH (a global land surface model), and examined the results in comparison with extensive growing-season field measurements over a mountain tundra area in northwestern Finland. Our results show that soil moisture varies considerably in the study area and this variation creates a mosaic of moisture conditions, ranging from dry ridges (growing season average 12 VWC%, Volumetric Water Content) to water-logged mires (65 VWC%). The models, particularly SpaFHy, simulated temporal soil moisture dynamics reasonably well in parts of the landscape, but both underestimated the range of variation spatially and temporally. Soil properties and topography were important drivers of spatial variation in soil moisture dynamics. By testing the applicability of two mechanistic models to predict fine-scale spatial and temporal variability in soil moisture, this study paves the way towards understanding the functioning of tundra ecosystems under climate change. This article is protected by copyright. All rights reserved.Peer reviewe