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Notes: We have investigated laser-assisted photochemical etching of InP in aqueous solutions without external electric fields. The process produces highly directional, high-aspect features with smooth vertical walls. Additionally, we demonstrate that the laser etching rate may be controlled externally by the application of a secondary light source.

Notes: Abstract The laser initiated formation of Cd-deposits from dimethylcadmium (DMCd) on quartz substrates has been investigated at various wavelengths between 337 and 676 nm. In this range substrate and DMCd are both transparent. The deposition mechanism is initiated by multiphoton dissociation of DMCd molecules adsorbed at the glass substrate and continues by pyrolysis of DMCd molecules at the laser-heated metallic deposit. Metal structures with a resolution below 1 μm have been obtained.

Notes: Abstract Deposition and etching processes based on the interaction of laser light with a substrate surface and molecules of the surrounding ambient are discussed in this tutorial review. This “laser writing” approach is based on photolytic, pyrolytic, or photoelectrochemical microreactions. The fundamental properties of such reactions and corresponding processing parameters (e.g. deposition or etch rate, resolution) are discussed. Important published results for deposition by photolysis, pyrolysis, and etching are summarized in the form of tables. A special list of potential applications for such techniques and a list of all materials used thus far for laser deposition and etching are included.

Notes: Abstract  Annual cycles of monthly albedos simulated with a general circulation model (GCM) are compared with surface observations. The data observed at 35 stations are retrieved from the Global Energy Balance Archive (GEBA) and drawn from the soil moisture and meteorological observations in the former Soviet Union. The model data are obtained with the ECHAM4 GCM in a ten-year simulation of the present-day climate at T106 resolution. The model calculated albedo values are modified before they are compared with the surface observations: They are interpolated to the stations and adjusted to account for altitude differences and fractional forest area. During the snow-free period, the model underestimates the albedo by up to 0.05 at the stations (with values between 0.2 and 0.25 measured over short grass) because the albedo for grassland is too low in the model. During the period with seasonal snow cover, the model underestimates the albedo by up to 0.2 at stations in Russia, Scandinavia and Canada, which experience severe winters. This underestimation is due to an oversimplified parameterization of the snow covered grid fraction and an inadequate linear relation between snow albedo and temperature. The derivative of albedo with respect to the forest fraction implemented in ECHAM is in line with the observations, although a small overestimation of the model’s gradient has been detected.

Notes: Abstract  A comprehensive dataset of direct observations is used to assess the representation of surface and atmospheric radiation budgets in general circulation models (GCMs). Based on combined measurements of surface and collocated top-of-the-atmosphere fluxes at more than 700 sites, a lack of absorption of solar radiation within the atmosphere is identified in the ECHAM3 GCM, indicating that the shortwave atmospheric absorption calculated in the current generation of GCMs, typically between 60 and 70 Wm-2, is too low by 10–20 Wm-2. The surface and atmospheric radiation budgets of a new version of the Max-Planck Institute GCM, the ECHAM4, differ considerably from other GCMs in both short- and longwave ranges. The amount of solar radiation absorbed in the atmosphere (90 Wm-2) is substantially larger than typically found in current GCMs, resulting in a lower absorption at the surface (147 Wm-2). It is shown that this revised disposition of solar energy within the climate system generally reduces the biases compared to the observational estimates of surface and atmospheric absorption. The enhanced shortwave absorption in the ECHAM4 atmosphere is due to an increase in both simulated clear-sky and cloud absorption compared to ECHAM3. The increased absorption in the cloud-free atmosphere is related to an enhanced absorption of water vapor, and is supported in stand-alone comparisons of the radiation scheme with synchronous observations. The increased cloud absorption, on the other hand, is shown to be predominantly spurious due to the coarse spectral resolution of the ECHAM4 radiation code, thus providing no physical explanation for the “anomalous cloud absorption” phenomenon. Quantitatively, however, an additional increase of atmospheric absorption due to clouds as in ECHAM4 is, at least at low latitudes, not in conflict with the observational estimates, though this does not rule out the possibility that other effects, such as highly absorbing aerosols, could equally contribute to close the gap between models and observations. At higher latitudes, however, the increased cloud absorption is not supported by the observational dataset. Overall, this study points out that not only the clouds, but also the cloud-free atmosphere might be responsible for the discrepancies between observational and simulated estimates of shortwave atmospheric absorption. The smaller absorption of solar radiation at the surface in ECHAM4 is compensated by an increased downward longwave flux (344 Wm-2), which is larger than in other GCMs. The enhanced downward longwave flux is supported by surface measurements and by a stand-alone validation of the radiation scheme for clear-sky conditions. The enhanced flux also ensures that a sufficient amount of energy is available at the surface to maintain a realistic intensity of the global hydrological cycle. In contrast, a one-handed revision of only the shortwave radiation budget to account for the increased shortwave absorption in GCM atmospheres may induce a global hydrological cycle that is too weak.

Notes: Abstract Deposition of micrometer-scale tungsten, molybdenum and platinum lines with the aid of the uv light from an argon-ion laser was investigated. Tungsten and molybdenum were deposited from their corresponding carbonyls and platinum from an acetylacetonate compound. High-quality metal conductors could be achieved for tungsten and platinum using a combined photolytic and pyrolytic, or “hybrid”, deposition scheme. The resistivity for these two deposited metals was approximately twice the bulk value. For molybdenum the deposition process was fast and dominated by the pyrolysis; the corresponding line resistivity was slightly higher than for the two other metals.