Global Dust Storm Research Articles

Atmospheric Circulation on Other Planets: Venus, Mars, Jupiter

Abstract. This review provides a comparative analysis of atmospheric circulation across four planets in our solar system: Venus, Mars, Jupiter, and Earth. By examining the unique characteristics of each planet, including atmospheric composition, rotation rates, axial tilt, and solar radiation, the study explores how these factors influence the dynamics of their respective atmospheres. Venus, with its dense CO atmosphere and slow retrograde rotation, exhibits a super-rotating atmosphere leading to extreme and uniform climate conditions. Marss thin atmosphere and significant seasonal variations, combined with global dust storms, result in highly variable and dynamic atmospheric patterns. Jupiters rapid rotation and internal heat contribute to complex and powerful atmospheric dynamics, including strong jet streams and long-lasting storms like the Great Red Spot. In contrast, Earth's atmospheric circulation is driven by a combination of solar radiation, rotation, and the presence of oceans and continents, resulting in relatively stable and predictable weather patterns. The study highlights the diversity of atmospheric processes within our solar system, providing insights that are crucial for understanding planetary climates and assessing the potential habitability of exoplanets.

Changes in Thermospheric Neutral and Ionic Species Densities during Global (2018) and Regional (2016) Scale Martian Dust Storms

Changes in Thermospheric Neutral and Ionic Species Densities during Global (2018) and Regional (2016) Scale Martian Dust Storms

The response of Martian photoelectron boundary to the 2018 global dust storm

The response of Martian photoelectron boundary to the 2018 global dust storm

Effects of the 2007 Martian Global Dust Storm on Boundary Positions in the Induced Magnetosphere

Mars's magnetosphere is a sensitive system, varying due to external and internal factors, such as solar wind conditions and crustal magnetic fields. A signature of this influence can be seen in the position of two boundaries; the bow shock and the induced magnetospheric boundary (IMB). The bow shock moves closer to Mars during times of high solar activity, and both the bow shock and IMB bulge away from Mars over crustal magnetic fields in the southern hemisphere. This study investigates whether large-scale atmospheric events at Mars have any signature in these two magnetic boundaries, by investigating the 2007 storm. The 2007 global storm lasted for several months and increased atmospheric temperatures and densities of both water vapor and carbon dioxide in the atmosphere, leading to an increase in atmospheric escape. Using Mars Express, we identified boundary locations before, during, and after the event, and compared these to modeled boundary locations and areographical locations on Mars. We find that, while it is unclear whether the bow shock position is impacted by the storm, the IMB location does change significantly, despite the orbital bias introduced by Mars Express. The terminator distance for the IMB peaks at longitudes 0°–40° and 310°–360°, leaving a depression around 180° longitude, where the boundary usually extends to higher altitudes due to the crustal magnetic fields. We suggest this may be due to the confinement of ionospheric plasma over crustal fields preventing mixing with the dust, creating a dip in ionospheric pressure here.

The Atmospheric Heating Mechanism over the Tharsis Bulge of Mars and the Impact of Global Dust Storms

Mars atmospheric dynamics are crucial for understanding its climate and weather patterns, especially over plateaus. Previous studies have explored localized atmospheric heating mechanisms over Mars plateaus only to a little extent. The local atmospheric heating dynamics over the Tharsis plateau, especially during global dust storms (GDSs), have not been quantitatively analyzed before. Based on reanalysis datasets, our analysis reveals that the central highlands of Tharsis experience ~130 K diurnal temperature fluctuations, driven by intense daytime convective activity. Surface temperature and near-surface air temperatures show fluctuations approximately 25 K and 20 K higher than those at similar latitudes, respectively. We quantify a super-adiabatic lapse rate around noon that suggests strong atmospheric instability, previously unquantified in this region. By dusk, the atmosphere stabilizes, presenting a homogenized condition. At aphelion, sensible heating and adiabatic terms control the atmospheric heating, while, at perihelion, radiative and sensible heating predominate. Notably, the onset of GDS significantly alters this dynamic, reducing the ground–air temperature gap from 17 K to 5 K and enhancing diabatic heating (adiabatic cooling) in the mid-to-lower (mid-to-upper) troposphere, with increases in radiative components up to 60 W/m2.

Minimum Mars Climate Sounder Retrieval Altitudes Reveal Cloud Altitudes at Aphelion and Stranded High-altitude Dust Following the MY34 Global Dust Storm on Mars

The Mars Climate Sounder (MCS) has been observing Mars’ atmosphere since the Mars Reconnaissance Orbiter’s arrival in 2006. While MCS can theoretically observe down to the surface, in practice the presence of aerosols such as dust and water ice can cut off retrievals at altitudes tens of kilometers above the surface. We examine the minimum cut-off altitudes of MCS temperature retrievals over the course of MCS's mission for the area around Gale Crater. We see a preference for cut-off altitudes above 20 km in the cloudy season and greater variation in preference in the dusty season. These cut-off altitudes can be used to infer cloud altitudes and to track the decay of significant dust storms as well as seeing the effects of stranded dust in the MY 34 global dust storm.

Tracking the south polar seasonal cap retreat of Mars using computer vision

We use daily polar stereographic mosaics obtained from the Mars Color Imager (MARCI) to autonomously track the recession of the South Polar Seasonal Cap (SPSC) during Mars Years (MYs) 28 to 31, for the period Ls = 178° to Ls = 345°. Utilizing an autonomous approach, we can delineate the SPSC by fitting an ellipse, offering the advantage of faster processing. This allows us to monitor the recession with enhanced time sampling capabilities. The SPSC recession is divided into two segments separated by a discontinuity at Ls = ∼260°, corresponding to the detachment of the Mountains of Mitchel seasonal cap from the main cap. Before the discontinuity, the SPSC exhibits variability where the recession rate can vary by up to 50%, with the fastest recession occurring at Ls = ∼235° and the slowest at Ls = ∼191°. After the discontinuity, the SPSC experiences reduced variability and undergoes a monotonic deceleration until Ls = ∼319°, gradually approaching the stable latitude of ∼86° S, consistent with the South Polar Residual Cap. MY 28 demonstrates distinct behavior in response to the Global Dust Storm (GDS), as the SPSC was smaller and sublimated faster before the onset of the storm compared to the 4-year average. Plain language summaryThe seasonal frost layer on Mars, consisting of frozen carbon dioxide, covers vast expanses during the winters. This frost forms as carbon dioxide gas in the atmosphere turns into solid ice on the surface, impacting the overall atmospheric pressure. We studied daily images captured by the Mars Color Imager (MARCI) to automatically monitor the retreat of the South Polar Seasonal Cap (SPSC) as it returns to the atmosphere during the spring over a span of four years. To achieve this, we employed a computer programming language called Python and a publicly available software library designed for visual analysis. By fitting an ellipse that most closely resembles the contour of the cap, we were able to trace and measure the change in the SPSC over time and determine how quickly SPSC shrinks. We discovered that our strategy produces results that are similar to those of previously published approaches, but in a lot less time and with increasing accuracy. We noticed new patterns in the seasonal retreat of the seasonal cap, including brief periods of faster shrinking, likely influenced by wind patterns. Additionally, we investigated a prominent icy area known as the Mountains of Mitchel seasonal cap and found that its behavior differed before and after a significant global dust storm in Mars Year 28.

Distribution of atmospheric aerosols during the 2007 Mars dust storm (MY 28): Solar infrared occultation observations by SPICAM

Solar occultation measurements by the SPICAM IR on Mars-Express have been used to study aerosol vertical distribution during the 2007 global dust storm (GDS) of Mars Year 28. Measurements in the near-IR spectral range from 1 to 1.7 μm provide information about aerosol optical properties, extinction coefficient, particle size and number density. The observations were performed at Ls = 254–302° of MY28 and latitudes from 65°S to 65°N. Within the SPICAM spectral range we could not distinguish between absorption due to dust or water ice. The particle size distribution and its parameters, the effective radius reff and variance νeff, are retrieved assuming either mineral dust or water ice refraction indices. Before the MY 28 GDS at Ls < 265° the aerosol was detected from 20 to 60 km with dust particle size ∼0.75 μm below 50 km and decreasing with altitude above. The detached layers, presumably consisting of water ice, were observed at ∼60 km in the Southern hemisphere and 45 km in the Northern and Southern hemispheres with opacity <0.02 and 0.01–0.15, respectively. The effective radius varied from 0.2 to 1.6 μm with number density from 0.4 to 50 cm−3. With the development of the GDS dust reached to 80 km and higher, while reff tended to increase with altitude up to 0.9–1 μm at 70–75 km. The dust number density decreased from 2 to 4 cm−3 at 40 km to 0.1 cm−3 at 70–80 km. The dependence of the effective variance on altitude and season has been studied. Before the beginning GDS νeff varied below 50–60 km from 0.2 to 0.4 in the Southern hemisphere to 0.4–0.6 in the Northern hemisphere. During the GDS, the wider distribution propagated higher, with νeff ∼ 0.5 up to 70 km in the southern hemisphere. In high latitudes of both hemispheres at Ls = 268–275° optically thin water ice high altitude clouds were detected at 80–90 km with reff < 0.5 μm and number density 10–100 cm−3.

A Comparative Analysis of Gravity Waves in He and Ar Densities in the Martian Thermosphere

AbstractIn this study, we conducted a comparative analysis of gravity waves (GWs) in the Martian upper thermosphere, utilizing He and Ar densities measured by the Neutral Gas and Ion Mass Spectrometer aboard the Mars Atmosphere and Volatile EvolutioN spacecraft. Our investigation revealed that GWs are a persistent phenomenon in Martian thermospheric He densities, akin to their presence in heavier species like Ar and CO2. Intriguingly, we observed that local time and seasonal variations in He GW amplitudes exhibit an almost opposite pattern compared to those in Ar. A significant breakthrough was the identification of a temperature‐dependent transition wavelength distinctly demarcating short and long wavelengths. This transition wavelength, which increases with increasing background temperatures, profoundly influences the dominance of GW amplitudes in He and Ar. In the short‐wavelength limit, GW amplitudes in He prevail, while GW amplitudes in Ar take precedence in the long‐wavelength limit. During periods of lower temperatures during midnight and the dawn terminator, transition wavelengths fall within the observed wavelength range enabling the study of dominance of GWs in He and Ar. Conversely, higher temperatures (&gt;180 K) during daytime and the dusk terminator eliminate transition wavelengths within our observational range. Consequently, the amplitudes of GWs in He dominate over those in Ar. Furthermore, under nominal dust conditions, GWs in both He and Ar exhibit an inverse relationship with their respective background densities. During global dust storm, this inverse relationship is maintained for GWs in He, while GWs in Ar display a slight positive correlation with background Ar densities.

Climatology of gravity wave activity based on two Martian years from ACS/TGO observations

Context. Gravity waves redistribute energy and momentum between the lower and upper atmosphere, thus providing vertical coupling between layers, and they affect the state, dynamics, and variability of the upper atmosphere. The statistics of gravity wave activity on Mars is poorly explored but is required in order to characterize the atmospheric circulation and to constrain numerical models. Aims. We present the gravity wave statistics accumulated over two Martian years: from the second half of Martian year 34 to the middle of Martian year 36 (May 2018 to February 2022). The statistics includes seasonal and latitude distributions of the wave potential energy and drag, serving to represent the wave activity and impact on the atmospheric dynamics. Methods. The observations were performed by the middle- and near-infrared spectrometers of the Atmospheric Chemistry Suite on board the ExoMars Trace Gas Orbiter. The temperature profiles we obtained independently from both channels during simultaneous measurements show a good agreement, thus providing verification and enhancing confidence in the data. The gravity wave parameters included amplitudes of temperature fluctuations, potential energy per unit mass, and wave drag. These parameters were retrieved at altitudes up to 160 and 100 km from the middle- and near-infrared channels, respectively. Results. A comparison of the data obtained during the global dust storm of Martian year 34 with the corresponding period of Martian year 35 without a storm revealed a reduction of wave activity in mid-latitudes, which is in agreement with previous observations, and enhancement in the polar regions of the southern hemisphere, which was not predicted by simulations with a high-resolution circulation model.

Far infrared radiative properties of Mars atmospheric aerosols and their application to Mars Climate Sounder retrievals of aerosol profiles, aerosol columns and surface temperatures

Limb sounding of thermal emission in the infrared wavelength range is a powerful technique for measuring temperature and aerosols in the martian atmosphere. However, the long optical path may provide challenges to limb retrievals in high aerosol conditions. These can be mitigated by considering limb measurements in the far infrared, where opacities of most aerosols are lower than in the mid-infrared. We present analyses of radiative properties of Mars dust and water ice aerosols at far infrared wavelengths based on measurements by the Mars Climate Sounder (MCS) in limb geometry at mid- and far infrared wavelengths. For dust aerosols, derived far infrared radiative properties show a homogeneous behavior that is consistent with particle sizes in the order of 1 μm effective radius. Far infrared radiative properties for water ice aerosols exhibit a larger variability in local time and region, leading to significant differences between the aphelion cloud belt and the north polar hood, with the resulting parameters suggesting particle sizes around 3 μm or larger. Using the derived parameters, we develop a method for retrieving aerosol profiles from MCS limb measurements that combines information from mid- and far infrared spectroscopic channels. The use of far infrared channels enables aerosol profile retrievals from limb measurements that typically reach about a scale height deeper into the atmosphere than would be possible using mid-infrared channels only. The extended vertical range of the aerosol profiles allows the derivation of aerosol column optical depths through vertical integration, with dust column derivations in global or large-scale regional dust storms also being available by extrapolating dust profiles below the lowest retrievable altitude of a limb measurement. The quantification of aerosol columns allows us to retrieve surface brightness temperatures from MCS on-planet viewing measurements that are corrected for atmospheric contributions. We show that differences between surface brightness and top-of-the-atmosphere temperatures are typically within 20 K, with surface brightness temperatures generally being warmer (colder) than top-of-the-atmosphere temperatures at daytime (nighttime), except at high latitudes.

Water Vapor Variability in the Thermosphere of Mars During Mars Years 32–36

AbstractUsing Mars Atmosphere and Volatile Evolution observations, we characterize the variability of water vapor in the Martian thermosphere during Mars Years 32–36. Near a fixed atmospheric pressure level of ∼5 × 10−7 Pa, the typical water density is 1.7 (±1.0) × 103 cm−3 and the typical water mixing ratio is 14.6 (±9.0) ppm. Thermospheric water levels are higher during the southern spring and summer seasons when Mars is near perihelion and there is significant dust loading in the lower atmosphere. However, the seasonal variation is not the same from year‐to‐year, likely due to annual differences in dust loading. Water vapor abundance is highly correlated with the amount of dust in the lower atmosphere, and increases during both regional and global dust storms. Additionally, there is a local time asymmetry with higher mixing ratios observed during morning local times, potentially caused by atmospheric circulation. Our results support previous work that found increased dust levels allow more water to be supplied directly to the thermosphere.

Comparing Atmospheric Temperature Fluctuations Across Landed Missions

AbstractWe analyze and compare atmospheric temperature data from three landed missions: Mars Science Laboratory (MSL) Curiosity rover, Phoenix lander, and Pathfinder lander. Pathfinder and Phoenix were lander missions that operated for 84 and 151 sols, respectively. MSL Curiosity is a rover that operates on the surface of Mars. It has recorded air temperature for more than five Mars Years (MY). We denoise and detrend temperature data from each mission and use those results to calculate variance in air temperature as a diagnostic for atmospheric variability at the surface. The results show a consistent seasonal pattern in MSL air temperature variance with little interannual variability outside major dust storms. The global dust storm in MY 34 was accompanied by a decrease in temperature variance and a muted response in peak MY 35 variance the following year. Phoenix (68°N, 2 m measurement height) and Pathfinder (19.7°N, 1.1 m measurement height) air temperatures have larger variance than air temperature from environmental data records at the MSL location (5.4°S, 1.6 m measurement height) at its equatorial latitude. Pathfinder variances per sol are larger than those of Phoenix, possibly due to a combination of Pathfinder's lower albedo surface and lower latitude. This occurs despite the Pathfinder location's higher thermal inertia, which would act to decrease noontime variance relative to a lower thermal inertia surface. Comparison of MSL temperature variance to pressure drops related to convective vortex activity shows consistent seasonal patterns; however, pressure drops tend to increase with increasing rover elevation, while variance remains consistent.

Pressure Deficit in Gale Crater and a Larger Northern Polar Cap After the MY34 Global Dust Storm

AbstractWe describe the model‐independent analysis technique of Mars Science Laboratory (MSL) pressure and Mars Climate Sounder (MCS) data in de la Torre Juárez et al. (2019, https://doi.org/10.22541/essoar.169945479.90436599/v1) that compared multiple years of surface pressures on Gale before, during, and after the Global Dust Storm of Mars Year 34. The analysis found (a) representative pressure scale heights over Gale; (b) that the storm was followed by a pressure deficit at Gale; (c) the following C storms did not eliminate the deficit; (d) changes in the duration of the polar caps condensation seasons, with an early start of the North Polar (NP) ice cap growing season the year before the Great Dust Storm (GDS) and a late signature of the end of the expansion season thereafter, changes consistent with a larger growth phase of the NP cap; (e) MCS observed a larger than usual NP cap; and (f) cold temperature anomalies over the NP and warm over the Southern Pole after the storm. We also show that the analysis of observed MSL pressure data alone filters out effects on the pressure signal that are attributable to dynamical and orographic processes in a recent model analysis that makes similar interpretations as our 2019 study. One additional Mars year of observations is included to eliminate early concerns about sensor drifts. Noting that a similar NP anomaly was observed with MCS data after the last early GDS in MY25, and not the later GDS of MY27, the results suggest a possible unique effect of early GDSs.

Comparison of Dust Storm Events between East Asia and North America

In this study, the decadal variations of global dust storm events (DSEs) are studied based on two typical cases that occurred in East Asia in 2023 and in North America in 1934, respectively. We found that the periods with weak winter monsoon, varied jet stream, weakened Siberian High (SH) and strengthening atmospheric blocking corresponded to the high incidence of DSEs in East Asia. In recent years, activity of the East Asian DSEs is active again because of the mutual effect of these four systems. Due to the ecological engineering projects in China, the frequency of the DSEs is less than that in Mongolia, whereas in Mongolia, the land degradation causes the frequency of DSEs to increase significantly. In the Great Plains of the United States, high incidence of the DSEs mainly corresponded to periods with strong atmospheric blocking in North America. Since the 1860s, the Great Plains had been affected by destruction of vegetation and drought, with bare soil swept into the air by the strong winds, resulting in “Dust Bowl” in the 1930s. Under the warning of long-term strong DSEs, the U.S. government issued a series of policies to respond to the impact of DSEs, which improved the ecosystem of the Great Plains. As a result of the improved ecosystem and weaker blocking activities in the Great Plains in the 1950s, activity of the DSEs was significantly weaker than that in the 1930s.

Effects of Global Dust Storms on Water Vapor in the Southern Polar Region of Mars

AbstractMartian global dust storms (GDS) can significantly affect the water cycle in the lower atmosphere (0−40 km). We compare the evolution of water vapor abundances, dust opacity and surface temperatures in the Southern Polar Region (SPR) during GDS years of MY25, MY28, and MY34 relative to years without GDS. During all GDS years, the vapor abundances decrease in the lower atmosphere in the SPR following the storm. Our results suggest that this decrease could be the result of disruption of the southward transport of vapor by atmospheric circulation. Alternatively, the decrease in vapor abundances could be caused by decreased desorption of vapor from the subsurface.

Retrievals of vertical distribution of Martian water vapor from combined day and night MGS TES nadir spectra

Vertical distribution of water vapor in the Martian lower atmosphere (0–40 km) is an important characteristic of the Martian water cycle. It reflects a complex interplay between various processes shaping the contemporary water cycle, including atmospheric transport, formation of water ice clouds, sublimation of surface frost, and possible interaction with the subsurface. Despite the growing dataset of water vapor observations, there is yet no comprehensive climatology of the vertical distribution of vapor. Limb and solar occultation observations that are typically used to retrieve vapor vertical distribution are much less numerous than nadir observations and are available for limited seasons and locations. We propose a new methodology to retrieve vertical distribution of water vapor in the Martian lower atmosphere using only nadir data. The methodology is based on the observation that infrared spectra collected over same location during different parts of day are sensitive to water vapor in different parts of the atmosphere. We validate our new methodology by applying it to infrared spectra simulated for realistic Mars environments created with Mars General Circulation Model (GCM). These tests show that vertical profiles of vapor can be recovered with accuracy ~20–40%, which is comparable to accuracy of limb and occultation observations. Importantly, the new retrieval algorithm can constrain near-surface (0–10 km) vapor abundances that cannot be observed by limb and occultation techniques. Application of this new methodology to a large dataset on Martian nadir spectra, such as the one collected by the Thermal Emission Spectrometer (TES) onboard Mars Global Surveyor (MGS) during its mission in 1999–2004, can result in the development of the detailed climatology of vapor vertical distribution on Mars. As an initial step toward this goal, we apply the new retrieval methodology to a subset of nadir spectra collected by MGS TES during one Martian year. The retrieved vapor profiles are qualitatively consistent with vapor distributions predicted by the GCM for different seasons. Differences between retrieved and simulated profiles can be interpreted as reflecting wetter Martian atmosphere and weaker atmospheric transport, during some seasons. Retrieved vapor distribution during southern summer suggests disruption of atmospheric vapor transport into southern extra-tropics following a global dust storm.

Revelations of interannual dune evolution from the swiftest aeolian system on Mars by MRO/HiRISE long-term monitoring

The north polar region of Mars, with its greater atmospheric pressure and vast inventory of ever-changing volatiles (e.g., CO2, H2O), hosts arguably the most active and diverse aeolian bedform systems on the planet. Here, we explore how these dune fields evolve spatiotemporally using up to 8 Mars years (16 Earth years) of MRO HiRISE observations to test the impact of various boundary conditions on annual mobility. A high degree of sand flux heterogeneity was observed for some dunes, whereas other sites displayed steady-state migration relative to long-term rates. These large changes in annual migration are attributed to the variable length of the frost-free seasons, sediment availability in relation to the timing of peak katabatic winds, and the influence of global dust storms on seasonal ice thickness. Consistent with our previous work, we continue to observe extremely high transport rates at Olympia Cavi. All stages of aeolian system evolution are observable (sand patch > protodune > dune), along with additional phenomena not previously observed outside of terrestrial settings (e.g., dune calving and collisions, remote transfer). Transitory protodunes may evolve from modest sand mounds to prominent barchans with slipfaces several meters tall within 3–5 Mars years, while adjacent duneforms may suffer slipfaces collapse as they lose sand supply. These Martian protodunes, which appear to be larger than terrestrial equivalents, and mature dunes found downwind are among the swiftest yet reported on Mars. These rapidly evolving cryo-aeolian systems provide a window into longer-term landscape evolution of non-polar dune fields.

Quantitative analysis of the Martian atmospheric dust cycle: Transported mass, surface dust lifting and sedimentation rates

The atmospheric dust cycle on Mars plays a dominant role in the planetary radiative balance, atmospheric photochemistry escape, and redistribution of materials on the surface. Although this planetary dust cycle has been extensively modelled and characterized with both orbital and in situ observations, to date little is known about the total mass of dust that is circulated, the actual dust lifting and settling rates, and the main dust sources and sinks. Using orbital global and seasonal measurements of atmospheric dust opacity, a data reduction methodology that can describe the annual dust redistribution cycle on a planetary scale with 95% accuracy is presented. The method was applied to the 9.3 μm infrared observations of the Thermal Emission Spectrometer (TES) aboard the Mars Global Surveyor (MGS) during two full Martian Years (MY) 25 and 26, and partly MY 24 and MY 27, disregarding the global dust storm that occurred in MY 25. By comparison with terrestrial observations, a mass-to-extinction conversion factor of 1.9 ± 0.3 g m−2 is proposed, assuming a dust density of 2.6 g cm−3. The analysis shows an estimation of 400 1012 g of dust transported globally in the atmosphere for a typical Mars year, which is comparable to the minimum total annual mass of dust transported on Earth. The methodology proposed here is based on remote sensing and cannot disentangle completely local surface lifting and sedimentation rates from dust advection. However, this analysis provides upper bounds which can be compared with in-situ observations. The analysis of the dust sedimentation cycle suggests that the annual cycle might produce a dust layer of about 50–100 μm on the surface of some particular zones, as Valle Marineris or Meridiani Planum. This estimation agrees with in-situ observations of rovers on Mars. The potential dust sources are mainly located from latitudes of 20°S to 60°S. Our results find the 70% of the sources previously identified by the existing planetary circulation models. This kind of large-scale analysis can be applied to other remote sensing observations to refine these calculations and study the annual and geographical variability of the dust-mass transport on Mars.

Water Vapor Vertical Distribution on Mars During Perihelion Season of MY 34 and MY 35 With ExoMars‐TGO/NOMAD Observations

AbstractThe water vapor in the Martian atmosphere plays a significant role in the planet's climate, being crucial in most of the chemical and radiative transfer processes. Despite its importance, the vertical distribution of H2O in the atmosphere has not still been characterized precisely enough. The recent ExoMars Trace Gas Orbiter mission, with its Nadir and Occultation for MArs Discovery instrument, has allowed us to measure the H2O vertical distribution with unprecedented resolution. Recent studies of vertical profiles have shown that high dust concentration in the atmosphere, in particular during dust storms, induces an efficient transport of the H2O to higher altitudes, from 40 km up to 80 km. We study the H2O vertical distribution in a subset of solar occultations during the perihelion of two Martian years (MYs), including the 2018 Global Dust Storm (GDS), in order to compare the same Martian season under GDS and non‐GDS conditions. We present our state‐of‐the‐art retrieval scheme, and we apply it to a combination of two diffraction orders, which permits sounding up to about 100 km. We confirm recent findings of H2O increasing at high altitudes during Ls = 190°–205° in MY 34, reaching abundances of about 150 ppmv at 80 km in both hemispheres not found during the same period of MY 35. We found a hygropause's steep rising during the GDS from 30 up to 80 km. Furthermore, strong supersaturation events have been identified at mesospheric altitudes even in presence of water ice layers retrieved by the IAA team.