During Biogenic Aerosols—Effects on Clouds and Climate (BAECC), the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) Program deployed the Second ARM Mobile Facility (AMF2) to Hyytiälä, Finland, for an 8-month intensive measurement campaign from February to September 2014. The primary research goal is to understand the role of biogenic aerosols in cloud formation. Hyytiälä is host to the Station for Measuring Ecosystem–Atmosphere Relations II (SMEAR II), one of the world’s most comprehensive surface in situ observation sites in a boreal forest environment. The station has been measuring atmospheric aerosols, biogenic emissions, and an extensive suite of parameters relevant to atmosphere–biosphere interactions continuously since 1996. Combining vertical profiles from AMF2 with surface-based in situ SMEAR II observations allows the processes at the surface to be directly related to processes occurring throughout the entire tropospheric column. Together with the inclusion of extensive surface precipitation measurements and intensive observation periods involving aircraft flights and novel radiosonde launches, the complementary observations provide a unique opportunity for investigating aerosol–cloud interactions and cloud-to-precipitation processes in a boreal environment. The BAECC dataset provides opportunities for evaluating and improving models of aerosol sources and transport, cloud microphysical processes, and boundary layer structures. In addition, numerical models are being used to bridge the gap between surface-based and tropospheric observations.

[1] In order to assess the influence of anthropogenic emissions on cloud albedo over Europe a reprocessed set of satellite measurements from 1985 to 1999 was investigated. Special emphasis was given to the Central European main emission area, including the so-called 'Black Triangle' which covered parts of Germany, the Czech Republic and Poland. Due to the decrease of aerosol precursor gases the analysis reveals a pronounced decrease of cloud albedo of about 2% from the late 80s to the late 90s. During winter in source regions of anthropogenic particulate matter emissions the cloud reflectance is more than 5% lower referring in addition to an absorption effect caused by black carbon in clouds. The comparison with emission data as well as model results of long range transport over Europe strongly supports the conclusion that the changed indirect aerosol effect is responsible for significantly changed cloud optical properties. Radiative transfer calculations indicate for the classical Twomey effect a change in radiative forcing of about 1.5 W/m 2 from the late 80s to the late 90s. In addition during winter a radiative forcing of about 3 W/m 2 due to the absorption effect for both the late 80s and the late 90s is estimated.

We construct a new SO(3)×SO(3) invariant non-supersymmetric solution of the bosonic field equations of D = 11 supergravity from the corresponding stationary point of maximal gauged N = 8 supergravity by making use of the non-linear uplift formulae for the metric and the 3-form potential. The latter are crucial as this solution appears to be inaccessible to traditional techniques of solving Einstein's field equations, and is arguably the most complicated closed form solution of this type ever found. The solution is also a promising candidate for a stable non-supersymmetric solution of M-theory uplifted from gauged supergravity. The technique that we present here may be applied more generally to uplift other solutions of gauged supergravity.