ALBERT

Description: We calculate the variation of spectral solar irradiance in the umbral shadow of the total solar eclipse of August 21, 2017 and compare it to observations. Starting from the sun's and moon's positions, we derive a realistic profile of the lunar shadow at the top of the atmosphere, including the effect of solar limb darkening. Subsequently, the Monte-Carlo model MYSTIC is used to simulate the transfer of solar radiation through the earth's atmosphere. Among the effects taken into account are the atmospheric state (pressure, temperature), concentrations of major gas constituents and the curvature of the earth, as well as the reflectance and elevation of the surrounding area. We apply the model to the total solar eclipse on August 21, 2017 at a position located in Oregon, where irradiance observations were performed for wavelengths between 306 nm and 1020 nm. The influence of the surface reflectance, the ozone profile and mountains surrounding the observer is investigated. An increased sensitivity during totality is found for the reflectance and topography, compared to non-eclipse conditions. During the eclipse, the irradiance at the surface does not only depend on the total ozone column (TOC) but also the vertical ozone distribution, which in general complicates derivations of the TOC from spectral surface irradiance. The findings are related to an analysis of the prevailing photon path and its difference compared to non-eclipse conditions. Using the most realistic estimate for each parameter, the model is compared to the irradiance observations. During totality, the relative difference between model and observations is less than 10 % in the spectral range from 400 nm to 1020 nm. Slightly larger deviations occur in the ultraviolet range below 400 nm and at 665 nm.

Description: We calculate the variation of spectral solar irradiance in the umbral shadow of the total solar eclipse of 21 August 2017 and compare it to observations. Starting from the Sun's and Moon's positions, we derive a realistic profile of the lunar shadow at the top of the atmosphere, including the effect of solar limb darkening. Subsequently, the Monte Carlo model MYSTIC (Monte Carlo code for the phYSically correct Tracing of photons In Cloudy atmospheres) is used to simulate the transfer of solar radiation through the Earth's atmosphere. Among the effects taken into account are the atmospheric state (pressure, temperature), concentrations of major gas constituents and the curvature of the Earth, as well as the reflectance and elevation of the surrounding area. We apply the model to the total solar eclipse on 21 August 2017 at a position located in Oregon, USA, where irradiance observations were performed for wavelengths between 306 and 1020 nm. The influence of the surface reflectance, the ozone profile, the mountains surrounding the observer and aerosol is investigated. An increased sensitivity during totality is found for the reflectance, aerosol and topography, compared to non-eclipse conditions. During the eclipse, the irradiance at the surface not only depends on the total ozone column (TOC) but also on the vertical ozone distribution, which in general complicates derivations of the TOC from spectral surface irradiance. The findings are related to an analysis of the prevailing photon path and its difference compared to non-eclipse conditions. Using the most realistic estimate for each parameter, the model is compared to the irradiance observations. During totality, the relative difference between model and observations is less than 10 % in the spectral range from 400 to 1020 nm. Slightly larger deviations occur in the ultraviolet range below 400 and at 665 nm.

Description: At Neumayer-Station in Antarctica snow height is permanently monitored with a laser distance meter. The instrument measures continuously since 2013-01-01 and is located in the vicinity of the Air Chemical Observatory Neumayer. By design, the sample area of the surface is on the order of a few millimetre in diameter. Long-term trends of the measured snow height are strongly correlated with accumulation on the ice shelf at a horizontal scale of several kilometres. Short-term trends reflect dynamic changes of the surface and can be used to deduce information on surface roughness.

Description: The meteorological observatory Neumayer continuously acquires meteorological parameters. Measurements are taken on or near the meteorological 10m-mast, located some 300m south-east of the main station building. Co-located there are BSRN (Baseline Surface Radiation Network) measurements taken. The measurement interval of the raw data is approximately 6s. Data is quality controlled: All measurements are checked daily on site and again prior to publication according to BSRN standards. Knowingly affected or erroneous data is removed.

Description: The meteorological observatory Neumayer continuously acquires meteorological parameters. Measurements are taken on or near the meteorological 10m-mast, located some 300m south-east of the main station building. Co-located there are BSRN (Baseline Surface Radiation Network) measurements taken. The measurement interval of the raw data is approximately 6s. Data is quality controlled: All measurements are checked daily on site and again prior to publication according to BSRN standards. Knowingly affected or erroneous data is removed.

Description: The meteorological observatory Neumayer continuously acquires meteorological parameters. Measurements are taken on or near the meteorological 10m-mast, located some 300m south-east of the main station building. Co-located there are BSRN (Baseline Surface Radiation Network) measurements taken. The measurement interval of the raw data is approximately 6s. Data is quality controlled: All measurements are checked daily on site and again prior to publication according to BSRN standards. Knowingly affected or erroneous data is removed.

Description: The meteorological observatory Neumayer continuously acquires meteorological parameters. Measurements are taken on or near the meteorological 10m-mast, located some 300m south-east of the main station building. Co-located there are BSRN (Baseline Surface Radiation Network) measurements taken. The measurement interval of the raw data is approximately 6s. Data is quality controlled: All measurements are checked daily on site and again prior to publication according to BSRN standards. Knowingly affected or erroneous data is removed.

Description: The meteorological observatory Neumayer continuously acquires meteorological parameters. Measurements are taken on or near the meteorological 10m-mast, located some 300m south-east of the main station building. Co-located there are BSRN (Baseline Surface Radiation Network) measurements taken. The measurement interval of the raw data is approximately 6s. Data is quality controlled: All measurements are checked daily on site and again prior to publication according to BSRN standards. Knowingly affected or erroneous data is removed.

Description: The meteorological observatory Neumayer continuously acquires meteorological parameters. Measurements are taken on or near the meteorological 10m-mast, located some 300m south-east of the main station building. Co-located there are BSRN (Baseline Surface Radiation Network) measurements taken. The measurement interval of the raw data is approximately 6s. Data is quality controlled: All measurements are checked daily on site and again prior to publication according to BSRN standards. Knowingly affected or erroneous data is removed.

Description: The meteorological observatory Neumayer continuously acquires meteorological parameters. Measurements are taken on or near the meteorological 10m-mast, located some 300m south-east of the main station building. Co-located there are BSRN (Baseline Surface Radiation Network) measurements taken. The measurement interval of the raw data is approximately 6s. Data is quality controlled: All measurements are checked daily on site and again prior to publication according to BSRN standards. Knowingly affected or erroneous data is removed.