Finnish Meteorological Institute

Drought responses of a Norway spruce forest on drained peat soil: combining sap-flow sensors, eddy-covariance, meteorological, soil and UAV data

Abstract. The summer of 2021 brought a severe drought to southern Finland. We explored how a drained boreal peatland forest responds to drought by combining a wide range of in situ monitoring and Unmanned Aerial Vehicle (UAV) remote sensing. A dataset combining eddy-covariance (E...

Consistent estimates of carbonyl sulfide and methane stratospheric lifetimes retrieved from AirCore profiles at different latitudes

Stratospheric loss is a major sink for both carbonyl sulfide (COS) and methane (CH 4 ), but their stratospheric lifetimes and sinks remain poorly constrained because high-resolution observations of their vertical distributions in the lower stratosphere are sparse. Here, we estima...

Quantifying Non‐Maxwellian Properties of Ion Populations During Reconnection at Earth's Magnetopause

Abstract We investigate ion velocity‐space features within the exhaust of magnetopause reconnection using a global hybrid‐Vlasov simulation. The Hermite transform and Gaussian Mixture Model (GMM) are applied to quantify the complexity of velocity‐space structures that arise durin...

Ionospheric currents and auroral signatures during successive earthward bursty bulk flows and dipolarization: a 7 December 2023 case study

Earthward bursty bulk flows (BBFs) in the central plasma sheet are frequently accompanied by dipolarization fronts, and together they account for a large fraction of the energy and momentum transported from the magnetotail to the high-latitude ionosphere through field-aligned cur...

Marine Heat Waves and Cold Spells – Multiple Analysis/Definitions (MHW-MAD): A Multi-Definition Global Marine Heatwave Database from Satellite Sea Surface Temperature Data

Marine heatwaves (MHWs) are prolonged anomalies of warm sea surface temperature (SST) that can disrupt marine ecosystems, physical climate processes, and human coastal activities. MHW definitions vary due to different stakeholders requirements, such as ecological scientists and c...

An Arctic climatology of particle number size distributions and cloud condensation nuclei during warm and moist intrusions

Abstract Recent studies indicate that warm and moist intrusions are significant sources of aerosols in the Arctic. Yet their contribution to different aerosol particle size modes, cloud condensation nuclei (CCN), and droplet number concentrations ( N d ) remains largely unconstra...

Consistency between zonal mean stratospheric and total column ozone trends (2000–2024)

This study presents an updated assessment of stratospheric and total column ozone trends over the 2000–2024 period using six merged limb-profile datasets and six merged total ozone datasets. Long-term changes were quantified using a multiple linear regression framework that accou...

Downscaling of SMAP Soil Moisture Based on the Transformer Algorithm in Anhui Province

Soil moisture (SM) is critical for climate, water, and agriculture, but Soil Moisture Active Passive (SMAP) passive microwave products have coarse resolution, limiting regional applications. This study develops an SM downscaling framework based on Transformer and its variants (Pa...

The Cold-Air Outbreaks in the Marine Boundary Layer Experiment model-observation intercomparison project (COMBLE-MIP) – Part 1: Model specification, observational constraints, and preliminary findings

Models struggle to represent the coupled microphysical, turbulent and radiative processes within widespread, long-lived marine cold-air outbreak (CAO) cloud fields, contributing to forecast and climate biases. Here we combine ground-based and satellite measurements to initialize...

Dune aurora: survey from a citizen science database

Abstract. Auroral forms can provide information not only on the state of near-Earth space but also on conditions in the lower-thermosphere–ionosphere. The so-called dune aurora, consisting of brighter stripes forming a wave-like pattern in the dim, diffuse green aurora, has been...

Estimating present temperature climate in a warming world: probabilistic verification of a model-based approach for years 2008–2025

Abstract When climate changes, statistics derived from past observations become unrepresentative of the true present climate. In 2008, Räisänen and Ruokolainen proposed a model-based method for alleviating this bias. Here, the fidelity of this method in predicting the probability...

Relationships between Arctic sea-ice concentration, temperature, and specific humidity in the lower troposphere during 1980–2021

Abstract. Understanding of the local effects of sea-ice concentration (SIC) variations on the Arctic atmosphere is a prerequisite for assessing the role of Arctic sea-ice decline in the climate system, including its influence on mid-latitudes. In this study, we analysed the relat...

Depolarization ratio of smoke and volcanic ash aerosol particles at 1565 nm using a HALO Doppler lidar

Abstract. Particle linear depolarization ratio is a widely used parameter in lidar research to distinguish different aerosol types and the thermodynamic phase of water. It is most frequently measured at ultraviolet and visible wavelengths (355 and 532 nm), yet multi-wavelength ob...

Europe’s extreme temperatures and rainfall in finer detail: strengths and limits of climate model downscaling

<title>Abstract</title> Climate extremes in Europe are becoming increasingly frequent and severe, heightening the need for reliable regional climate information to support preparedness and adaptation. Downscaled climate model (DCM) products are widely used for this purpose. Yet,...

Total Ozone Reactivity Measurements Reveal Knowledge Gap in Volatile Organic Compound Emissions and Their Reactions

Abstract Total ozone (O 3 ) reactivity monitors (TORMs) were used to investigate biogenic volatile organic compound (BVOC) emissions from several ecosystems. Measurements were conducted in temperate deciduous North American forests, during the CABINEX and SOAS campaigns, on tundr...