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: The World Ocean produces a large amount of natural aerosols that have all impact on the Earth's albedo and climate. Sea-salt is the major contributor to aerosol optical depth over the oceans. [Mahowald et al. 2006; Chin et al. 2002; Satheesh et al. 1999; Winter and Chylek, 1997] and therefore affects the radiative balance over the ocean through the direct [Haywood et al. 1999] and indirect aerosol effect [O'Dowd et al. 1999]. Aerosols over the oceans (produced marine and advected from land sources) are important for various atmospheric processes [Lewis and Schwartz, 2004] and remote sensing studies [Gordon, 1997].

Description: A statistical approach is used to assess the quality of the MISR Version 22 (V22) aerosol products. Aerosol Optical Depth (AOD) retrieval results are improved relative to the early post- launch values reported by Kahn et al. [2005a], varying with particle type category. Overall, about 70% to 75% of MISR AOD retrievals fall within 0.05 or 20% AOD of the paired validation data, and about 50% to 55% are within 0.03 or 10% AOD, except at sites where dust, or mixed dust and smoke, are commonly found. Retrieved particle microphysical properties amount to categorical values, such as three groupings in size: "small," "medium," and "large." For particle size, ground-based AERONET sun photometer Angstrom Exponents are used to assess statistically the corresponding MISR values, which are interpreted in terms of retrieved size categories. Coincident Single-Scattering Albedo (SSA) and fraction AOD spherical data are too limited for statistical validation. V22 distinguishes two or three size bins, depending on aerosol type, and about two bins in SSA (absorbing vs. non-absorbing), as well as spherical vs. non-spherical particles, under good retrieval conditions. Particle type sensitivity varies considerably with conditions, and is diminished for mid-visible AOD below about 0.15 or 0.2. Based on these results, specific algorithm upgrades are proposed, and are being investigated by the MISR team for possible implementation in future versions of the product.

Description: We analyze two LLBL crossings made by Interball Tail satellite under southward or variable magnetosheath magnetic field: one crossing on the flank of the magnetosphere, and another one closer to the subsolar point. Three different types of ion velocity distributions within LLBL are observed: (a) D-shaped distributions, (b) ion velocity distributions consisting of two counter-streaming components of magnetosheath-ty and (c) distributions with three components one of which has nearly zero parallel velocity and two counter-streaming components. Only the (a) type fits to the single magnetic flux tube formed by reconnection between magnetospheric and magnetosheath magnetic fields. We argue that two counter-streaming magnetosheath-like ion components observed by Interball within LLBL cannot be explained by the reflection of the ions from the magnetic mirror deeper within magnetosphere. Types (b) and (c) ion velocity distributions would form within spiral magnetic flux tube consisting of a mixture of alternating segments originating from the magnetosheath and from magnetospheric plasma. The shapes of ion velocity distributions and their evolution with decreasing number density in LLBL indicate that a significant part of LLBL is located on magnetic field lines of long spiral flux tube islands at the magnetopause, as has been proposed and found to occur in magnetopause simulations. We consider these observations as evidence for multiple reconnection X-ray lines between magnetosheath and magnetospheric flux tubes.

Description: The Interball/Tail spacecraft crossed the high latitude magnetopause near the cusp region under stable northward IMF conditions on 29 May 1996, with magnetic local time and magnetic latitude approx. 7.3 hours, approx. 65.4 degrees, respectively. The Interball Tail spacecraft observed quasi-steady reconnection and a relatively stable reconnection site at high latitudes. Observed sunward plasma flow and tangential stress balance indicated that reconnection occurred poleward of the magnetic cusp, above the spacecraft location. The spacecraft observed sub-alfvenic flow in the magnetosheath region adjacent to the magnetopause current layer near the reconnection site indicating that the reconnection site may have moved in the sunward direction. These observations suggest that the region of sub-alfvenic flow and stable, quasi-steady reconnection extend to very high latitudes under northward IMF conditions which is not consistent with the gas dynamic model predictions.