Comparison of middle- and low-latitude sodium layer from a ground-based lidar network, the Odin satellite, and WACCM-Na model
Bingkun Yu1,2,Xianghui Xue1,3,4,5,6,Christopher J. Scott2,Mingjiao Jia7,Wuhu Feng8,9,John M. C. Plane8,Daniel R. Marsh8,10,Jonas Hedin11,Jörg Gumbel11,and Xiankang Dou1,12Bingkun Yu et al.Bingkun Yu1,2,Xianghui Xue1,3,4,5,6,Christopher J. Scott2,Mingjiao Jia7,Wuhu Feng8,9,John M. C. Plane8,Daniel R. Marsh8,10,Jonas Hedin11,Jörg Gumbel11,and Xiankang Dou1,12
1CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, China
2Department of Meteorology, University of Reading, Berkshire, UK
3CAS Center for Excellence in Comparative Planetology, Hefei, China
4Anhui Mengcheng Geophysics National Observation and Research Station, University of Science and Technology of China, Hefei, China
5Hefei National Laboratory for the Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, China
6Frontiers Science Center for Planetary Exploration and Emerging Technologies, University of Science and Technology of China, Hefei, China
7Shandong Guoyao Quantum Lidar Co., Ltd., Jinan, Shandong, China
8School of Chemistry, University of Leeds, Leeds, UK
9National Center for Atmospheric Science, University of Leeds, Leeds, UK
10National Center for Atmospheric Research, Boulder, CO, USA
11Department of Meteorology, Stockholm University, Stockholm, Sweden
12Electronic Information School, Wuhan University, Wuhan, China
1CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, China
2Department of Meteorology, University of Reading, Berkshire, UK
3CAS Center for Excellence in Comparative Planetology, Hefei, China
4Anhui Mengcheng Geophysics National Observation and Research Station, University of Science and Technology of China, Hefei, China
5Hefei National Laboratory for the Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, China
6Frontiers Science Center for Planetary Exploration and Emerging Technologies, University of Science and Technology of China, Hefei, China
7Shandong Guoyao Quantum Lidar Co., Ltd., Jinan, Shandong, China
8School of Chemistry, University of Leeds, Leeds, UK
9National Center for Atmospheric Science, University of Leeds, Leeds, UK
10National Center for Atmospheric Research, Boulder, CO, USA
11Department of Meteorology, Stockholm University, Stockholm, Sweden
12Electronic Information School, Wuhan University, Wuhan, China
Received: 10 Apr 2022 – Discussion started: 12 May 2022
Abstract. The ground-based measurements obtained from a lidar network and the six-year OSIRIS limb-scanning radiance measurements made by the Odin satellite are used to study the climatology of the middle- and low-latitude sodium (Na) layer. Up to January 2021, four Na resonance fluorescence lidars at Beijing (40.2° N, 116.2° E), Hefei (31.8° N, 117.3° E), Wuhan (30.5° N, 114.4° E), and Haikou (19.5° N, 109.1° E) collected vertical profiles of Na density for a total of 2,136 nights (19,587 h). These large datasets provide routine long-term measurements of the Na layer with exceptionally high temporal and vertical resolution. The lidar measurements are particularly useful for filling in OSIRIS data gaps since the OSIRIS measurements were not made during the dark winter months because they utilise the solar-pumped resonance fluorescence from Na atoms. The observations of Na layers from the ground-based lidars and the satellite are comprehensively compared with a global model of meteoric Na in the atmosphere (WACCM-Na). The lidars present a unique test of OSIRIS and WACCM, because they cover the latitude range along 120° E longitude in an unusual geographic location with significant gravity wave generation. In general, good agreement is found between lidar observations, satellite measurements, and WACCM simulations. Whereas the Na number density from OSIRIS is slightly larger than that from the Na lidars at the four stations within one standard deviation of the OSIRIS monthly average, particularly in autumn and early winter arising from significant uncertainties in Na density retrieved from much less satellite radiance measurements. WACCM underestimates the seasonal variability of the Na layer observed at the lower latitude lidar stations (Wuhan and Haikou). This discrepancy suggests the seasonal variability of vertical constituent transport modeled in WACCM is underestimated because much of the gravity wave spectrum is not captured in the model.
This manuscript discusses Na-layer lidar observations taken at four stations in China: Beijing, Hefei, Wuhan, and Haikou. All lidar stations are around 110E and span the latitudes from about 19N to 40N. These dataset offers a unique opportunity to study Na-layer and its relation to dynamics, chemistry and electrodynamics. The lidar measurements are then compared to satellite observations and model simulations with WACCM-Na, a version of a climate model that includes. The main conclusions of the study are a general agreement between observations but with significant discrepancies at times attributed to the lack of space-borne observations during norther winter in the darkness; and, a general disagreement between the model on the observations in terms of variability. In particular, the authors suggest that model variability can be improved with a better representation of the spectrum of subgrid gravity waves.
A few comments/queries below:
Line 122: Please define what S4max (or S4 index) is for the non-experts.
4 & 6. Please use the same contour min/max for ease of comparison.
Line 170. Could the horizontal resolution be the problem in resolving those fine structures/peaks?
Line 181: Is it sub-sampling by 5 days or is it a 5-day average?
Figure 8: I seem to detect a quasi-biennial oscillation. Any thoughts?
Line 187: replace less with few
Figure 9c: I almost missed the vertical bars: maybe add the station name for clarity?
Line 203-206: I don’t understand what is implied here. Is the suggestion that lack of field line transport is a potential issue for WACCM-Na? How’s that so? I thought WACCM transports ions as part of the chemistry package.
Line 268: The sentences need some clarifications. I think the authors want to say that the limited resolution of sub-grid processes could explain the lack of variability. I buy that. However, the sentence seems to indicate that WACCM is missing all gravity wave and turbulence. And I don’t buy that.
Figure 14: Isn’t the seasonal variability also different between OSIRIS and CMP lidars?
Lines 349-351: The disagreement is more than slight. More importantly, how is it that fewer observations result in a high bias?
We present a study on the climatology of the metal sodium layer in the upper atmosphere, from the ground-based measurements obtained from a lidar network, the Odin satellite measurements, and a global model of meteoric sodium in the atmosphere. Comprehensively comparisons show good agreement and some discrepancies between ground-based observations, satellite measurements, and global model simulations.
We present a study on the climatology of the metal sodium layer in the upper atmosphere, from...
