DYAMOND: the DYnamics of the Atmospheric general circulation Modeled On Non-hydrostatic Domains

Abstract A review of the experimental protocol and motivation for DYAMOND, the first intercomparison project of global storm-resolving models, is presented. Nine models submitted simulation output for a 40-day (1 August–10 September 2016) intercomparison period. Eight of these employed a tiling of the sphere that was uniformly less than 5 km. By resolving the transient dynamics of convective storms in the tropics, global storm-resolving models remove the need to parameterize tropical deep convection, providing a fundamentally more sound representation of the climate system and a more natural link to commensurately high-resolution data from satellite-borne sensors. The models and some basic characteristics of their output are described in more detail, as is the availability and planned use of this output for future scientific study. Tropically and zonally averaged energy budgets, precipitable water distributions, and precipitation from the model ensemble are evaluated, as is their representation of tropical cyclones and the predictability of column water vapor, the latter being important for tropical weather.

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Zonal Wave 3 Pattern in the Southern Hemisphere generated by tropical convection

10.21203/rs.3.rs-320008/v1 ◽

2021 ◽

Author(s):

Rishav Goyal ◽

Martin Jucker ◽

Alex Sen Gupta ◽

Harry Hendon ◽

Matthew England

Keyword(s):

Sea Ice ◽

Atmospheric Circulation ◽

Southern Hemisphere ◽

Ocean Circulation ◽

General Circulation ◽

Deep Convection ◽

Circulation Model ◽

Hadley Cell ◽

Wave Source ◽

The Tropics

Abstract A distinctive feature of the Southern Hemisphere (SH) extratropical atmospheric circulation is the quasi-stationary zonal wave 3 (ZW3) pattern, characterized by three high and three low-pressure centers around the SH extratropics. This feature is present in both the mean atmospheric circulation and its variability on daily, seasonal and interannual timescales. While the ZW3 pattern has significant impacts on meridional heat transport and Antarctic sea ice extent, the reason for its existence remains uncertain, although it has long been assumed to be linked to the existence of three major land masses in the SH extratropics. Here we use an atmospheric general circulation model to show that the stationery ZW3 pattern is instead driven by zonal asymmetric deep atmospheric convection in the tropics, with little to no role played by the orography or land masses in the extratropics. Localized regions of deep convection in the tropics form a local Hadley cell which in turn creates a wave source in the subtropics that excites a poleward and eastward propagating wave train which forms stationary waves in the SH high latitudes. Our findings suggest that changes in tropical deep convection, either due to natural variability or climate change, will impact the zonal wave 3 pattern, with implications for Southern Hemisphere climate, ocean circulation, and sea-ice.

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Contribution of Tropical Cyclones to Global Very Deep Convection

Journal of Climate ◽

10.1175/jcli-d-13-00085.1 ◽

2014 ◽

Vol 27 (11) ◽

pp. 4313-4336 ◽

Cited By ~ 7

Author(s):

Haiyan Jiang ◽

Cheng Tao

Keyword(s):

Tropical Cyclones ◽

Deep Convection ◽

Convective Available Potential Energy ◽

Tropical Rainfall Measuring Mission ◽

Precipitable Water ◽

Moisture Exchange ◽

Derived Properties ◽

Trmm Precipitation ◽

The Tropics ◽

Heat And Moisture

Abstract Based on the 12-yr (1998–2009) Tropical Rainfall Measuring Mission (TRMM) precipitation feature (PF) database, both radar and infrared (IR) observations from TRMM are used to quantify the contribution of tropical cyclones (TCs) to very deep convection (VDC) in the tropics and to compare TRMM-derived properties of VDC in TCs and non-TCs. Using a radar-based definition, it is found that the contribution of TCs to total VDC in the tropics is not much higher than the contribution of TCs to total PFs. However, the area-based contribution of TCs to overshooting convection defined by IR is 13.3%, which is much higher than the 3.2% contribution of TCs to total PFs. This helps explain the contradictory results between previous radar-based and IR-based studies and indicates that TCs only contribute disproportionately large amount of overshooting convection containing mainly small ice particles that are barely detected by the TRMM radar. VDC in non-TCs over land has the highest maximum 30- and 40-dBZ height and the strongest ice-scattering signature derived from microwave 85- and 37-GHz observations, while VDC in TCs has the coldest minimum IR brightness temperature and largest overshooting distance and area. This suggests that convection is much more intense in non-TCs over land but is much deeper or colder in TCs. It is found that VDC in TCs usually has smaller environmental shear but larger total precipitable water and convective available potential energy than those in non-TCs. These findings offer evidence that TCs may contribute disproportionately to troposphere-to-stratosphere heat and moisture exchange.

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A Five-Year Radar-Based Climatology of Tropopause Folds and Deep Convection over Wales, United Kingdom

Monthly Weather Review ◽

10.1175/mwr-d-12-00246.1 ◽

2013 ◽

Vol 141 (5) ◽

pp. 1693-1707 ◽

Cited By ~ 11

Author(s):

Bogdan Antonescu ◽

Geraint Vaughan ◽

David M. Schultz

Keyword(s):

United Kingdom ◽

Deep Convection ◽

Moist Convection ◽

Isolated Cells ◽

Very High Frequency ◽

High Resolution Data ◽

Convective Storms ◽

Deep Moist Convection ◽

Upper Level ◽

Western Side

AbstractA five-year (2006–10) radar-based climatology of tropopause folds and convective storms was constructed for Wales, United Kingdom, to determine how deep, moist convection is modulated by tropopause folds. Based on the continuous, high-resolution data from a very high frequency (VHF) wind-profiling radar located at Capel Dewi, Wales, 183 tropopause folds were identified. Tropopause folds were most frequent in January with a secondary maximum in July. Based on data from the U.K. weather radar network, a climatology of 685 convective storms was developed. The occurrence of convective storms was relatively high year-round except for an abrupt minimum in February–April. Multicellular lines (43.5%) were the most common morphology with a maximum in October, followed by isolated cells (33.1%) with a maximum in May–September, and nonlinear clusters (23.4%) with a maximum in November–January. Convective storms were associated with 104 (56.8%) of the tropopause folds identified in this study, with the association strongest in December. Of the 55 tropopause folds observed on the eastern side of an upper-level trough, 37 (67.3%) were associated with convective storms, most commonly in the form of multicellular lines. Of the 128 tropopause folds observed on the western side of an upper-level trough, 42 (32.8%) were associated with convective storms, most commonly isolated cells. These results suggest that more organized storms tend to form in environments favorable for synoptic-scale ascent.

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The Amazon Dense GNSS Meteorological Network: A New Approach for Examining Water Vapor and Deep Convection Interactions in the Tropics

Bulletin of the American Meteorological Society ◽

10.1175/bams-d-13-00171.1 ◽

2015 ◽

Vol 96 (12) ◽

pp. 2151-2165 ◽

Cited By ~ 27

Author(s):

David K. Adams ◽

Rui M. S. Fernandes ◽

Kirk L. Holub ◽

Seth I. Gutman ◽

Henrique M. J. Barbosa ◽

...

Keyword(s):

Water Vapor ◽

Diurnal Cycle ◽

Numerical Models ◽

Deep Convection ◽

Precipitable Water ◽

Sea Breeze ◽

Tropical Meteorology ◽

Precipitable Water Vapor ◽

Gnss Meteorology ◽

The Tropics

Abstract The complex interactions between water vapor fields and deep atmospheric convection remain one of the outstanding problems in tropical meteorology. The lack of high spatial–temporal resolution, all-weather observations in the tropics has hampered progress. Numerical models have difficulties, for example, in representing the shallow-to-deep convective transition and the diurnal cycle of precipitation. Global Navigation Satellite System (GNSS) meteorology, which provides all-weather, high-frequency (5 min), precipitable water vapor estimates, can help. The Amazon Dense GNSS Meteorological Network experiment, the first of its kind in the tropics, was created with the aim of examining water vapor and deep convection relationships at the mesoscale. This innovative, Brazilian-led international experiment consisted of two mesoscale (100 km × 100 km) networks: 1) a 1-yr (April 2011–April 2012) campaign (20 GNSS meteorological sites) in and around Manaus and 2) a 6-week (June 2011) intensive campaign (15 GNSS meteorological sites) in and around Belem, the latter in collaboration with the Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud-Resolving Modeling and to the Global Precipitation Measurement (CHUVA) Project in Brazil. Results presented here from both networks focus on the diurnal cycle of precipitable water vapor associated with sea-breeze convection in Belem and seasonal and topographic influences in and around Manaus. Ultimately, these unique observations may serve to initialize, constrain, or validate precipitable water vapor in high-resolution models. These experiments also demonstrate that GNSS meteorology can expand into logistically difficult regions such as the Amazon. Other GNSS meteorology networks presently being constructed in the tropics are summarized.

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Gravity wave variances and propagation derived from AIRS radiances

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-1701-2012 ◽

2012 ◽

Vol 12 (4) ◽

pp. 1701-1720 ◽

Cited By ~ 55

Author(s):

J. Gong ◽

D. L. Wu ◽

S. D. Eckermann

Keyword(s):

Gravity Wave ◽

General Circulation ◽

Deep Convection ◽

General Circulation Models ◽

Satellite Orbits ◽

Atmospheric Infrared Sounder ◽

Quasi Biennial Oscillation ◽

Mountain Ranges ◽

The Tropics ◽

Cross Track

Abstract. As the first gravity wave (GW) climatology study using nadir-viewing infrared sounders, 50 Atmospheric Infrared Sounder (AIRS) radiance channels are selected to estimate GW variances at pressure levels between 2–100 hPa. The GW variance for each scan in the cross-track direction is derived from radiance perturbations in the scan, independently of adjacent scans along the orbit. Since the scanning swaths are perpendicular to the satellite orbits, which are inclined meridionally at most latitudes, the zonal component of GW propagation can be inferred by differencing the variances derived between the westmost and the eastmost viewing angles. Consistent with previous GW studies using various satellite instruments, monthly mean AIRS variance shows large enhancements over meridionally oriented mountain ranges as well as some islands at winter hemisphere high latitudes. Enhanced wave activities are also found above tropical deep convective regions. GWs prefer to propagate westward above mountain ranges, and eastward above deep convection. AIRS 90 field-of-views (FOVs), ranging from +48° to −48° off nadir, can detect large-amplitude GWs with a phase velocity propagating preferentially at steep angles (e.g., those from orographic and convective sources). The annual cycle dominates the GW variances and the preferred propagation directions for all latitudes. Indication of a weak two-year variation in the tropics is found, which is presumably related to the Quasi-biennial oscillation (QBO). AIRS geometry makes its out-tracks capable of detecting GWs with vertical wavelengths substantially shorter than the thickness of instrument weighting functions. The novel discovery of AIRS capability of observing shallow inertia GWs will expand the potential of satellite GW remote sensing and provide further constraints on the GW drag parameterization schemes in the general circulation models (GCMs).

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Moisture and Moist Static Energy Budgets of South Asian Monsoon Low Pressure Systems in GFDL AM4.0

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-17-0309.1 ◽

2018 ◽

Vol 75 (6) ◽

pp. 2107-2123 ◽

Cited By ~ 11

Author(s):

Ángel F. Adames ◽

Yi Ming

Keyword(s):

General Circulation ◽

Deep Convection ◽

Linear Regression Analysis ◽

Maximum Amplitude ◽

Circulation Model ◽

Radiative Heating ◽

Eastern Coast ◽

Energy Budgets ◽

Moist Static Energy ◽

Static Energy

Abstract The mechanisms that lead to the propagation of anomalous moisture and moist static energy (MSE) in monsoon low and high pressure systems, collectively referred to as synoptic-scale monsoonal disturbances (SMDs), are investigated using daily output fields from GFDL’s atmospheric general circulation model, version 4.0 (AM4.0). On the basis of linear regression analysis of westward-propagating rainfall anomalies of time scales shorter than 15 days, it is found that SMDs are organized into wave trains of three to four individual cyclones and anticyclones. These events amplify over the Bay of Bengal, reach a maximum amplitude over the eastern coast of India, and dissipate as they approach the Arabian Sea. The structure and propagation of the simulated SMDs resemble those documented in observations. It is found that moisture and MSE anomalies exhibit similar horizontal structures in the simulated SMDs, indicating that moisture is the leading contributor to MSE. Propagation of the moisture anomalies is governed by vertical moisture advection, while the MSE anomalies propagate because of horizontal advection of dry static energy by the anomalous winds. By combining the budgets, we interpret the propagation of the moisture anomalies in terms of lifting that is forced by horizontal dry static energy advection, that is, ascent along sloping isentropes. This process moistens the lower free troposphere, producing an environment that is more favorable to deep convection. Ascent driven by radiative heating is of primary importance to the maintenance of the moisture anomalies.

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The Anatomy of a Series of Cloud Bursts that Eclipsed the US Rainfall Record

Monthly Weather Review ◽

10.1175/mwr-d-21-0028.1 ◽

2021 ◽

Keyword(s):

Deep Convection ◽

Vertical Motion ◽

Precipitable Water ◽

Radar Data ◽

Data Sets ◽

Streamwise Vorticity ◽

Convective Storms ◽

Low Level ◽

The Us ◽

The Right

Abstract A series of extreme cloudbursts occurred on 14 April 2018 over the northern slopes of the island of Kaua‘i. The storm inundated some areas with 1262 mm (∼50”) of rainfall in a 24-hr period, eclipsing the previous 24-hr US rainfall record of 1100 mm (42”) set in Texas in 1979. Three periods of intense rainfall are diagnosed through detailed analysis of National Weather Service operational and special data sets. On the synoptic scale, a slowly southeastward propagating trough aloft over a deep layer of low level moisture (>40 mm of total precipitable water) produced prolonged instability over Kaua‘i. Enhanced NE to E low level flow impacted Kaua‘i’s complex terrain, which includes steep north and eastward facing slopes and cirques. The resulting orographic lift initiated deep convection. The wind profile exhibited significant shear in the troposphere and streamwise vorticity within the convective storm inflow. Evidence suggests that large directional shear in the boundary layer, paired with enhanced orographic vertical motion, produced rotating updrafts within the convective storms. Mesoscale rotation is manifest in the radar data during the latter two periods and reflectivity cores are observed to propagate both to the left and to the right of the mean shear, which is characteristic of supercells. The observations suggest that the terrain configuration in combination with the windshear separates the area of updrafts from the downdraft section of the storm, resulting in almost continuous heavy rainfall over Waipā Garden.

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Quality-Controlled Upper-Air Sounding Dataset for DYNAMO/CINDY/AMIE: Development and Corrections

Journal of Atmospheric and Oceanic Technology ◽

10.1175/jtech-d-13-00165.1 ◽

2014 ◽

Vol 31 (4) ◽

pp. 741-764 ◽

Cited By ~ 76

Author(s):

Paul E. Ciesielski ◽

Hungjui Yu ◽

Richard H. Johnson ◽

Kunio Yoneyama ◽

Masaki Katsumata ◽

...

Keyword(s):

Deep Convection ◽

Precipitable Water ◽

Eastern Africa ◽

Operational Model ◽

Heating Effects ◽

Surface Data ◽

Quality Checks ◽

The Indian Ocean ◽

High Vertical Resolution ◽

The Tropics

Abstract The upper-air sounding network for Dynamics of the Madden–Julian Oscillation (DYNAMO) has provided an unprecedented set of observations for studying the MJO over the Indian Ocean, where coupling of this oscillation with deep convection first occurs. With 72 rawinsonde sites and dropsonde data from 13 aircraft missions, the sounding network covers the tropics from eastern Africa to the western Pacific. In total nearly 26 000 soundings were collected from this network during the experiment’s 6-month extended observing period (from October 2011 to March 2012). Slightly more than half of the soundings, collected from 33 sites, are at high vertical resolution. Rigorous post–field phase processing of the sonde data included several levels of quality checks and a variety of corrections that address a number of issues (e.g., daytime dry bias, baseline surface data errors, ship deck heating effects, and artificial dry spikes in slow-ascent soundings). Because of the importance of an accurate description of the moisture field in meeting the scientific goals of the experiment, particular attention is given to humidity correction and its validation. The humidity corrections, though small relative to some previous field campaigns, produced high-fidelity moisture analyses in which sonde precipitable water compared well with independent estimates. An assessment of operational model moisture analyses using corrected sonde data shows an overall good agreement with the exception at upper levels, where model moisture and clouds are more abundant than the sonde data would indicate.

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The Response of Tropical Atmospheric Energy Budgets to ENSO*

Journal of Climate ◽

10.1175/jcli-d-12-00681.1 ◽

2013 ◽

Vol 26 (13) ◽

pp. 4710-4724 ◽

Cited By ~ 22

Author(s):

Michael Mayer ◽

Kevin E. Trenberth ◽

Leopold Haimberger ◽

John T. Fasullo

Keyword(s):

El Niño ◽

El Nino ◽

Southern Oscillation ◽

Warm Pool ◽

Smooth Transition ◽

Energy Budgets ◽

Enso Events ◽

El Niño Modoki ◽

Static Energy ◽

The Tropics

Abstract The variability of zonally resolved tropical energy budgets in association with El Niño–Southern Oscillation (ENSO) is investigated. The most recent global atmospheric reanalyses from 1979 to 2011 are employed with removal of apparent discontinuities to obtain best possible temporal homogeneity. The growing length of record allows a more robust analysis of characteristic patterns of variability with cross-correlation, composite, and EOF methods. A quadrupole anomaly pattern is found in the vertically integrated energy divergence associated with ENSO, with centers over the Indian Ocean, the Indo-Pacific warm pool, the eastern equatorial Pacific, and the Atlantic. The smooth transition, particularly of the main maxima of latent and dry static energy divergence, from the western to the eastern Pacific is found to require at least two EOFs to be adequately described. The canonical El Niño pattern (EOF-1) and a transition pattern (EOF-2; referred to as El Niño Modoki by some authors) form remarkably coherent ENSO-related anomaly structures of the tropical energy budget not only over the Pacific but throughout the tropics. As latent and dry static energy divergences show strong mutual cancellation, variability of total energy divergence is smaller and more tightly coupled to local sea surface temperature (SST) anomalies and is mainly related to the ocean heat discharge and recharge during ENSO peak phases. The complexity of the structures throughout the tropics and their evolution during ENSO events along with their interactions with the annual cycle have often not been adequately accounted for; in particular, the El Niño Modoki mode is but part of the overall evolutionary patterns.

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