ALBERT

Description: The measurements were carried out 27 March–6 April 2020 on small ice-covered shallow Lake Vendyurskoe (62.215784N, 33.262784E, North-Western of Russia). Surface area of the lake is 10.4 km2, its mean and maximal depths are 5.3 and 13.4 m. The maximal length of the lake is 7 km; and the average width is 1.5 km. The mooring equipment was deployed on the ice 350 m from the northern shore, with a location depth of ~ 7 m. The measuring complex included a pyranometer placed directly under the ice to measure downwelling irradiance (a M-80m universal pyranometer, produced in Russia, accuracy 1 W m-2, sampling frequency one minute), two Star-shaped pyranometers (Theodor Friderich & Co, Meteorologishe Gerate und Systeme, Germany, accuracy 0.2 W/m2, sampling interval one minute) placed at one meter above ice surface to measure downwelling and upwelling irradiance, thermistor chain (13 temperature sensors TR-1060 RBR, Canada, accuracy ±0.002°C, resolution ±0.00005°C, sampling frequency 10 s; sensors were placed at intervals of 0.5 m, starting from 0.2 m from the ice bottom to a depth of 6.2 m), and two ADCPs (2 MHz HR Aquadopp current velocity profiler, Nortek AS, Norway). The two ADCPs were mounted on a special retaining frame that rigidly fixed the instruments on the ice and to each other. Both devices were installed in a hole with emitters located 3 cm below the lower ice boundary. For the entire measurement period, the devices were set up as follows: signal discreteness was one minute (32 pulses with a frequency of 2 Hz), depth scanning range was 2.875 m (115 cells with a size of 25 mm). To exclude the mutual influence of the two ADCPs, the emitters were set in an asynchronous mode with a 30 s delay. In the first stage of experiment – from 17:00 LT (local time = UTC + 3 h) on 27 March 2020 to 09:30 LT on 30 March 2020 – the ADCPs emitters were located at a distance of 1.5 m from each other, and at a depth of 1.61 m one beam from each of the devices intersected. In the second stage – from 10:00 LT on 30 March 2020 to 10:00 LT on 6 April 2020 – the distance between the emitters was 0.75 m and two pairs of beams intersected at the same depth.

Description: The measurements were carried out 27 March–6 April 2020 on small ice-covered shallow Lake Vendyurskoe (62.215784N, 33.262784E, North-Western of Russia). Surface area of the lake is 10.4 km2, its mean and maximal depths are 5.3 and 13.4 m. The maximal length of the lake is 7 km; and the average width is 1.5 km. The mooring equipment was deployed on the ice 350 m from the northern shore, with a location depth of ~ 7 m. The measuring complex included a pyranometer placed directly under the ice to measure downwelling irradiance (a M-80m universal pyranometer, produced in Russia, accuracy 1 W m-2, sampling frequency one minute), two Star-shaped pyranometers (Theodor Friderich & Co, Meteorologishe Gerate und Systeme, Germany, accuracy 0.2 W/m2, sampling interval one minute) placed at one meter above ice surface to measure downwelling and upwelling irradiance, thermistor chain (13 temperature sensors TR-1060 RBR, Canada, accuracy ±0.002°C, resolution ±0.00005°C, sampling frequency 10 s; sensors were placed at intervals of 0.5 m, starting from 0.2 m from the ice bottom to a depth of 6.2 m), and two ADCPs (2 MHz HR Aquadopp current velocity profiler, Nortek AS, Norway). The two ADCPs were mounted on a special retaining frame that rigidly fixed the instruments on the ice and to each other. Both devices were installed in a hole with emitters located 3 cm below the lower ice boundary. For the entire measurement period, the devices were set up as follows: signal discreteness was one minute (32 pulses with a frequency of 2 Hz), depth scanning range was 2.875 m (115 cells with a size of 25 mm). To exclude the mutual influence of the two ADCPs, the emitters were set in an asynchronous mode with a 30 s delay. In the first stage of experiment – from 17:00 LT (local time = UTC + 3 h) on 27 March 2020 to 09:30 LT on 30 March 2020 – the ADCPs emitters were located at a distance of 1.5 m from each other, and at a depth of 1.61 m one beam from each of the devices intersected. In the second stage – from 10:00 LT on 30 March 2020 to 10:00 LT on 6 April 2020 – the distance between the emitters was 0.75 m and two pairs of beams intersected at the same depth.

Description: The measurements were carried out 27 March–6 April 2020 on small ice-covered shallow Lake Vendyurskoe (62.215784N, 33.262784E, North-Western of Russia). Surface area of the lake is 10.4 km2, its mean and maximal depths are 5.3 and 13.4 m. The maximal length of the lake is 7 km; and the average width is 1.5 km. The mooring equipment was deployed on the ice 350 m from the northern shore, with a location depth of ~ 7 m. The measuring complex included a pyranometer placed directly under the ice to measure downwelling irradiance (a M-80m universal pyranometer, produced in Russia, accuracy 1 W m-2, sampling frequency one minute), two Star-shaped pyranometers (Theodor Friderich & Co, Meteorologishe Gerate und Systeme, Germany, accuracy 0.2 W/m2, sampling interval one minute) placed at one meter above ice surface to measure downwelling and upwelling irradiance, thermistor chain (13 temperature sensors TR-1060 RBR, Canada, accuracy ±0.002°C, resolution ±0.00005°C, sampling frequency 10 s; sensors were placed at intervals of 0.5 m, starting from 0.2 m from the ice bottom to a depth of 6.2 m), and two ADCPs (2 MHz HR Aquadopp current velocity profiler, Nortek AS, Norway). The two ADCPs were mounted on a special retaining frame that rigidly fixed the instruments on the ice and to each other. Both devices were installed in a hole with emitters located 3 cm below the lower ice boundary. For the entire measurement period, the devices were set up as follows: signal discreteness was one minute (32 pulses with a frequency of 2 Hz), depth scanning range was 2.875 m (115 cells with a size of 25 mm). To exclude the mutual influence of the two ADCPs, the emitters were set in an asynchronous mode with a 30 s delay. In the first stage of experiment – from 17:00 LT (local time = UTC + 3 h) on 27 March 2020 to 09:30 LT on 30 March 2020 – the ADCPs emitters were located at a distance of 1.5 m from each other, and at a depth of 1.61 m one beam from each of the devices intersected. In the second stage – from 10:00 LT on 30 March 2020 to 10:00 LT on 6 April 2020 – the distance between the emitters was 0.75 m and two pairs of beams intersected at the same depth.

Description: The measurements were carried out 27 March–6 April 2020 on small ice-covered shallow Lake Vendyurskoe (62.215784N, 33.262784E, North-Western of Russia). Surface area of the lake is 10.4 km2, its mean and maximal depths are 5.3 and 13.4 m. The maximal length of the lake is 7 km; and the average width is 1.5 km. The mooring equipment was deployed on the ice 350 m from the northern shore, with a location depth of ~ 7 m. The measuring complex included a pyranometer placed directly under the ice to measure downwelling irradiance (a M-80m universal pyranometer, produced in Russia, accuracy 1 W m-2, sampling frequency one minute), two Star-shaped pyranometers (Theodor Friderich & Co, Meteorologishe Gerate und Systeme, Germany, accuracy 0.2 W/m2, sampling interval one minute) placed at one meter above ice surface to measure downwelling and upwelling irradiance, thermistor chain (13 temperature sensors TR-1060 RBR, Canada, accuracy ±0.002°C, resolution ±0.00005°C, sampling frequency 10 s; sensors were placed at intervals of 0.5 m, starting from 0.2 m from the ice bottom to a depth of 6.2 m), and two ADCPs (2 MHz HR Aquadopp current velocity profiler, Nortek AS, Norway). The two ADCPs were mounted on a special retaining frame that rigidly fixed the instruments on the ice and to each other. Both devices were installed in a hole with emitters located 3 cm below the lower ice boundary. For the entire measurement period, the devices were set up as follows: signal discreteness was one minute (32 pulses with a frequency of 2 Hz), depth scanning range was 2.875 m (115 cells with a size of 25 mm). To exclude the mutual influence of the two ADCPs, the emitters were set in an asynchronous mode with a 30 s delay. In the first stage of experiment – from 17:00 LT (local time = UTC + 3 h) on 27 March 2020 to 09:30 LT on 30 March 2020 – the ADCPs emitters were located at a distance of 1.5 m from each other, and at a depth of 1.61 m one beam from each of the devices intersected. In the second stage – from 10:00 LT on 30 March 2020 to 10:00 LT on 6 April 2020 – the distance between the emitters was 0.75 m and two pairs of beams intersected at the same depth.

Description: The measurements were carried out 27 March–6 April 2020 on small ice-covered shallow Lake Vendyurskoe (62.215784N, 33.262784E, North-Western of Russia). Surface area of the lake is 10.4 km2, its mean and maximal depths are 5.3 and 13.4 m. The maximal length of the lake is 7 km; and the average width is 1.5 km. The mooring equipment was deployed on the ice 350 m from the northern shore, with a location depth of ~ 7 m. The measuring complex included a pyranometer placed directly under the ice to measure downwelling irradiance (a M-80m universal pyranometer, produced in Russia, accuracy 1 W m-2, sampling frequency one minute), two Star-shaped pyranometers (Theodor Friderich & Co, Meteorologishe Gerate und Systeme, Germany, accuracy 0.2 W/m2, sampling interval one minute) placed at one meter above ice surface to measure downwelling and upwelling irradiance, thermistor chain (13 temperature sensors TR-1060 RBR, Canada, accuracy ±0.002°C, resolution ±0.00005°C, sampling frequency 10 s; sensors were placed at intervals of 0.5 m, starting from 0.2 m from the ice bottom to a depth of 6.2 m), and two ADCPs (2 MHz HR Aquadopp current velocity profiler, Nortek AS, Norway). The two ADCPs were mounted on a special retaining frame that rigidly fixed the instruments on the ice and to each other. Both devices were installed in a hole with emitters located 3 cm below the lower ice boundary. For the entire measurement period, the devices were set up as follows: signal discreteness was one minute (32 pulses with a frequency of 2 Hz), depth scanning range was 2.875 m (115 cells with a size of 25 mm). To exclude the mutual influence of the two ADCPs, the emitters were set in an asynchronous mode with a 30 s delay. In the first stage of experiment – from 17:00 LT (local time = UTC + 3 h) on 27 March 2020 to 09:30 LT on 30 March 2020 – the ADCPs emitters were located at a distance of 1.5 m from each other, and at a depth of 1.61 m one beam from each of the devices intersected. In the second stage – from 10:00 LT on 30 March 2020 to 10:00 LT on 6 April 2020 – the distance between the emitters was 0.75 m and two pairs of beams intersected at the same depth.

Description: The measurements were carried out 27 March–6 April 2020 on small ice-covered shallow Lake Vendyurskoe (62.215784N, 33.262784E, North-Western of Russia). Surface area of the lake is 10.4 km2, its mean and maximal depths are 5.3 and 13.4 m. The maximal length of the lake is 7 km; and the average width is 1.5 km. The mooring equipment was deployed on the ice 350 m from the northern shore, with a location depth of ~ 7 m. The measuring complex included a pyranometer placed directly under the ice to measure downwelling irradiance (a M-80m universal pyranometer, produced in Russia, accuracy 1 W m-2, sampling frequency one minute), two Star-shaped pyranometers (Theodor Friderich & Co, Meteorologishe Gerate und Systeme, Germany, accuracy 0.2 W/m2, sampling interval one minute) placed at one meter above ice surface to measure downwelling and upwelling irradiance, thermistor chain (13 temperature sensors TR-1060 RBR, Canada, accuracy ±0.002°C, resolution ±0.00005°C, sampling frequency 10 s; sensors were placed at intervals of 0.5 m, starting from 0.2 m from the ice bottom to a depth of 6.2 m), and two ADCPs (2 MHz HR Aquadopp current velocity profiler, Nortek AS, Norway). The two ADCPs were mounted on a special retaining frame that rigidly fixed the instruments on the ice and to each other. Both devices were installed in a hole with emitters located 3 cm below the lower ice boundary. For the entire measurement period, the devices were set up as follows: signal discreteness was one minute (32 pulses with a frequency of 2 Hz), depth scanning range was 2.875 m (115 cells with a size of 25 mm). To exclude the mutual influence of the two ADCPs, the emitters were set in an asynchronous mode with a 30 s delay. In the first stage of experiment – from 17:00 LT (local time = UTC + 3 h) on 27 March 2020 to 09:30 LT on 30 March 2020 – the ADCPs emitters were located at a distance of 1.5 m from each other, and at a depth of 1.61 m one beam from each of the devices intersected. In the second stage – from 10:00 LT on 30 March 2020 to 10:00 LT on 6 April 2020 – the distance between the emitters was 0.75 m and two pairs of beams intersected at the same depth.

Description: Detailed knowledge of hydrogen Sulfide absorption spectra is important for terrestrial remote sensing applications and investigations of atmospheric chemistry in Venus and other planets.

Description: An extreme biomass-burning event occurred in Indonesia from September through October 2015 due to severe drought conditions, partially caused by a major El Nino event, thereby allowing for significant burning of peatland that had been previously drained. This event had the highest sustained aerosol optical depths (AOD) ever monitored by the global Aerosol Robotic Network (AERONET). The newly developed AERONET Version 3 algorithms retain high AOD at the longer wavelengths when associated with high Angstrom Exponents (AEs), which thereby allowed for measurements of AOD at 675 nanometers as high as approximately 7, the upper limit of Sun photometry. Measured AEs at the highest monitored AOD levels were subsequently utilized to estimate instantaneous values of AOD at 550 nanometers in the range of 11 to 13, well beyond the upper measurement limit. Additionally, retrievals of complex refractive indices, size distributions, and single scattering albedos (SSA) were obtained at much higher AOD levels than possible from almucantar scans due to the ability to perform retrievals at smaller solar zenith angles with new hybrid sky radiance scans. For retrievals made at the highest AOD levels the fine mode volume median radii were approximately 0.25 to 0.30 microns, which are very large particles for biomass burning. Very high SSA values (approximately 0.975 from 440 to 1020 nanometers) are consistent with the domination by smoldering combustion of peat burning. Estimates of the percentage peat contribution to total biomass burning aerosol based on retrieved SSA and laboratory measured peat SSA were approximately 80-85 percent, in excellent agreement with independent estimates.

Description: Analysis of sun photometer measured and satellite retrieved aerosol optical depth (AOD) data has shown that major aerosol pollution events with very high fine mode AOD (〉1.0 in mid-visible) in the China/Korea/Japan region are often observed to be associated with significant cloud cover. This makes remote sensing of these events difficult even for high temporal resolution sun photometer measurements. Possible physical mechanisms for these events that have high AOD include a combination of aerosol humidification, cloud processing, and meteorological co-variation with atmospheric stability and convergence. The new development of Aerosol Robotic network (AERONET) Version 3 Level 2 AOD with improved cloud screening algorithms now allow for unprecedented ability to monitor these extreme fine mode pollution events. Further, the Spectral Deconvolution Algorithm (SDA) applied to Level 1 data (L1; no cloud screening) provides an even more comprehensive assessment of fine mode AOD than L2 in current and previous data versions. Studying the 2012 winter-summer period, comparisons of AERONET L1 SDA daily average fine mode AOD data showed that Moderate Resolution Imaging Spectroradiometer (MODIS) satellite remote sensing of AOD often did not retrieve and/or identify some of the highest fine mode AOD events in this region. Also, compared to models that include data assimilation of satellite retrieved AOD, the L1 SDA fine mode AOD was significantly higher in magnitude, particularly for the highest AOD events that were often associated with significant cloudiness.

Description: As a representative site of the southern African biomass-burning region, sun-sky data from the 15 year Aerosol Robotic Network (AERONET) deployment at Mongu, Zambia, was analyzed. For the biomass-burning season months (July-November), we investigate seasonal trends in aerosol single scattering albedo (SSA), aerosol size distributions, and refractive indices from almucantar sky scan retrievals. The monthly mean single scattering albedo at 440 nm in Mongu was found to increase significantly from approx.. 0.84 in July to approx. 0.93 in November (from 0.78 to 0.90 at 675 nm in these same months). There was no significant change in particle size, in either the dominant accumulation or secondary coarse modes during these months, nor any significant trend in the Angstrom exponent (440-870 nm; r(exp 2) = 0.02). A significant downward seasonal trend in imaginary refractive index (r(exp 2) = 0.43) suggests a trend of decreasing black carbon content in the aerosol composition as the burning season progresses. Similarly, burning season SSA retrievals for the Etosha Pan, Namibia AERONET site also show very similar increasing single scattering albedo values and decreasing imaginary refractive index as the season progresses. Furthermore, retrievals of SSA at 388 nm from the Ozone Monitoring Instrument satellite sensor show similar seasonal trends as observed by AERONET and suggest that this seasonal shift is widespread throughout much of southern Africa. A seasonal shift in the satellite retrieval bias of aerosol optical depth from the Moderate Resolution Imaging Spectroradiometer collection 5 dark target algorithm is consistent with this seasonal SSA trend since the algorithm assumes a constant value of SSA. Multi-angle Imaging Spectroradiometer, however, appears less sensitive to the absorption-induced bias.