Evaluation of the Sensitivity of Medicane Ianos to Model Microphysics and Initial Conditions Using Satellite Measurements

Tropical-like cyclone (TLC or medicane) Ianos formed during mid-September 2020 over the Southern Mediterranean Sea, and, during its mature stage on days 17–18, it affected southern Italy and especially Greece and its Ionian islands, where it brought widespread disruption due to torrential rainfall, severe wind gusts, and landslides, causing casualties. This study performs a sensitivity analysis of the mature phase of TLC Ianos with the WRF model to different microphysics parameterization schemes and initial and boundary condition (IBC) datasets. Satellite measurements from the Global Precipitation Measurement Mission-Core Observatory (GPM-CO) dual-frequency precipitation radar (DPR) and the Advanced Scatterometer (ASCAT) sea-surface wind field were used to verify the WRF model forecast quality. Results show that the model is most sensitive to the nature of the IBC dataset (spatial resolution and other dynamical and physical differences), which better defines the primary mesoscale features of Ianos (low-level vortex, eyewall, and main rainband structure) when using those at higher resolution (~25 km versus ~50 km) independently of the microphysics scheme, but with the downside of producing too much convection and excessively low minimum surface pressures. On the other hand, no significant differences emerged among their respective trajectories. All experiments overestimated the vertical extension of the main rainbands and display a tendency to shift the system to the west/northwest of the actual position. Especially among the experiments with the higher-resolution IBCs, the more complex WRF microphysics schemes (Thompson and Morrison) tended to outperform the others in terms of rain rate forecast and most of the other variables examined. Furthermore, WSM6 showed a good performance while WDM6 was generally the least accurate. Lastly, the calculation of the cyclone phase space diagram confirmed that all simulations triggered a warm-core storm, and all but one also exhibited axisymmetry at some point of the studied lifecycle.

Download Full-text

Sea surface wind speed and sea state retrievals from dual-frequency altimeter and its preliminary application in global view of wind-sea and swell distributions

International Journal of Remote Sensing ◽

10.1080/01431161.2018.1433889 ◽

2018 ◽

Vol 39 (10) ◽

pp. 3076-3093 ◽

Cited By ~ 4

Author(s):

Shuiqing Li ◽

Hui Shen ◽

Yijun Hou ◽

Yijun He ◽

Fan Bi

Keyword(s):

Surface Wind ◽

Surface Wind Speed ◽

Sea Surface ◽

Dual Frequency ◽

Sea State ◽

Sea Surface Wind Speed ◽

Sea Surface Wind ◽

Global View ◽

Wind Sea ◽

Preliminary Application

Download Full-text

Determination of sea surface wind speed using the polarimetric and multidirectional properties of satellite measurements in visible bands

Geophysical Research Letters ◽

10.1029/2012gl053508 ◽

2012 ◽

Vol 39 (19) ◽

pp. n/a-n/a ◽

Cited By ~ 17

Author(s):

Tristan Harmel ◽

Malik Chami

Keyword(s):

Wind Speed ◽

Surface Wind ◽

Surface Wind Speed ◽

Sea Surface ◽

Satellite Measurements ◽

Sea Surface Wind Speed ◽

Sea Surface Wind

Download Full-text

High-Resolution Simulations of the 2010 Pakistan Flood Event: Sensitivity to Parameterizations and Initialization Time

Journal of Hydrometeorology ◽

10.1175/jhm-d-15-0098.1 ◽

2016 ◽

Vol 17 (4) ◽

pp. 1147-1167 ◽

Cited By ~ 9

Author(s):

Francesca Viterbo ◽

Jost von Hardenberg ◽

Antonello Provenzale ◽

Luca Molini ◽

Antonio Parodi ◽

...

Keyword(s):

Large Scale ◽

Initial Conditions ◽

Distributed Simulation ◽

Wrf Model ◽

Tropical Rainfall Measuring Mission ◽

Indus Basin ◽

High Mountain ◽

Microphysics Scheme ◽

Earth Observing System ◽

The Impact

Abstract Estimating the risk of flood-generating precipitation events in high-mountain regions with complex orography is a difficult but crucial task. Quantitative precipitation forecasts (QPFs) at fine resolution are an essential ingredient to address this issue. Along these lines, the ability of the Weather Research and Forecasting (WRF) Model, operated at 3.5-km grid spacing, to reproduce the extreme meteorological event that led to the 2010 Pakistan flood and produced heavy monsoonal rain in the Indus basin is explored. The model results are compared with Tropical Rainfall Measuring Mission (TRMM) rainfall estimates, the available ground measurements, and radar observations from the CloudSat mission. In particular, the sensitivity of the WRF simulations to the use of different convective closures (explicit and Kain–Fritsch) and microphysical parameterizations (WRF single-moment 6-class microphysics scheme and Thompson) is analyzed. The impact of using different initial conditions, associated with a different initialization day, is also examined. The use of the new-generation Distributed Simulation and Stimulation System NASA Earth Observing System Simulators Suite radar simulator allows a more accurate and extensive representation of the mesoscale processes and of the interaction with the complex orography. The results reported here indicate that the quality of the large-scale initial conditions is a prominent factor affecting the possibility of retrieving a realistic representation of this event when using a nonhydrostatic regional model.

Download Full-text

Numerical Investigations of Atmospheric Rivers and the Rain Shadow over the Santa Clara Valley

Atmosphere ◽

10.3390/atmos10030114 ◽

2019 ◽

Vol 10 (3) ◽

pp. 114 ◽

Cited By ~ 2

Author(s):

Dalton Behringer ◽

Sen Chiao

Keyword(s):

San Francisco ◽

Wrf Model ◽

Cloud Microphysics ◽

The Other ◽

Microphysics Scheme ◽

Atmospheric Rivers ◽

Bright Band ◽

Warm Rain ◽

Double Moment ◽

Warm Rain Process

This study investigated precipitation distribution patterns in association with atmospheric rivers (ARs). The Weather Research and Forecasting (WRF) model was employed to simulate two strong atmospheric river events. The precipitation forecasts were highly sensitive to cloud microphysics parameterization schemes. Thus, radar observed and simulated Z H and Z D R were evaluated to provide information about the drop-size distribution (DSD). Four microphysics schemes (WSM-5, WSM-6, Thompson, and WDM-6) with nested simulations (3 km, 1 km, and 1/3 km) were conducted. One of the events mostly contained bright-band (BB) rainfall and lasted less than 24 h, while the other contained both BB and non-bright-band (NBB) rainfall, and lasted about 27 h. For each event, there was no clear improvement in the 1/3 km model, over the 1 km model. Overall, the WDM-6 microphysics scheme best represented the rainfall and the DSD. It appears that this scheme performed well, due to its relative simplicity in ice and mixed-phase microphysics, while providing double-moment predictions of warm rain microphysics (i.e., cloud and rain mixing ratio and number concentration). The other schemes tested either provided single-moment predictions of all classes or double-moment predictions of ice and rain (Thompson). Considering the shallow nature of precipitation in atmospheric rivers and the high-frequency of the orographic effect enhancing the warm rain process, these assumptions appear to be applicable over the southern San Francisco Bay Area.

Download Full-text

Sensitivity of WRF cloud microphysics to simulations of a severe thunderstorm event over Southeast India

Annales Geophysicae ◽

10.5194/angeo-28-603-2010 ◽

2010 ◽

Vol 28 (2) ◽

pp. 603-619 ◽

Cited By ~ 108

Author(s):

M. Rajeevan ◽

A. Kesarkar ◽

S. B. Thampi ◽

T. N. Rao ◽

B. Radhakrishna ◽

...

Keyword(s):

Land Surface ◽

Initial Conditions ◽

Surface Wind ◽

Wrf Model ◽

Cloud Microphysics ◽

Severe Thunderstorm ◽

Severe Convection ◽

Wind Measurements ◽

Simulated Surface ◽

Southeast India

Abstract. In the present study, we have used the Weather Research and Forecasting (WRF) model to simulate the features associated with a severe thunderstorm observed over Gadanki (13.5° N, 79.2° E), over southeast India, on 21 May 2008 and examined its sensitivity to four different microphysical (MP) schemes (Thompson, Lin, WSM6 and Morrison). We have used the WRF model with three nested domains with the innermost domain of 2 km grid spacing with explicit convection. The model was integrated for 36 h with the GFS initial conditions of 00:00 UTC, 21 May 2008. For validating simulated features of the thunderstorm, we have considered the vertical wind measurements made by the Indian MST radar installed at Gadanki, reflectivity profiles by the Doppler Weather Radar at Chennai, and automatic weather station data at Gadanki. There are major differences in the simulations of the thunderstorm among the MP schemes, in spite of using the same initial and boundary conditions and model configuration. First of all, all the four schemes simulated severe convection over Gadanki almost an hour before the observed storm. The DWR data suggested passage of two convective cores over Gadanki on 21 May, which was simulated by the model in all the four MP schemes. Comparatively, the Thompson scheme simulated the observed features of the updraft/downdraft cores reasonably well. However, all the four schemes underestimated strength and vertical extend of the updraft cores. The MP schemes also showed problems in simulating the downdrafts associated with the storm. While the Thompson scheme simulated surface rainfall distribution closer to observations, the other three schemes overestimated observed rainfall. However, all the four MP schemes simulated the surface wind variations associated with the thunderstorm reasonably well. The model simulated reflectivity profiles were consistent with the observed reflectivity profile, showing two convective cores. These features are consistent with the simulated condensate profiles, which peaked around 5–6 km. As the results are dependent on initial conditions, in simulations with different initial conditions, different schemes may become closer to observations. The present study suggests not only large sensitivity but also variability of the microphysical schemes in the simulations of the thunderstorm. The study also emphasizes the need for a comprehensive observational campaign using multi-observational platforms to improve the parameterization of the cloud microphysics and land surface processes over the Indian region.

Download Full-text

Two-frequency acoustic-gravitational waves, simulation of satellite measurements

Kinematika i fizika nebesnyh tel (Online) ◽

10.15407/kfnt2020.06.022 ◽

2020 ◽

Vol 36 (6) ◽

pp. 22-36

Author(s):

E.I. Kryuchkov ◽

I.T. Zhuk ◽

O.K. Cheremnykh

Keyword(s):

Gravity Waves ◽

Natural Frequencies ◽

Initial Conditions ◽

Spectral Characteristics ◽

Single Frequency ◽

Center Frequency ◽

Dual Frequency ◽

Satellite Measurements ◽

Acoustic Gravity Waves ◽

Isothermal Atmosphere

The theory of acoustic gravity waves (AGW) considers free disturbances of the atmosphere within the framework of a single-frequency approach. In this case, the theory implies the existence of two separate types of waves with different natural frequencies - acoustic and gravitational. In the single-frequency approach, wave fluctuations of density, temperature, and velocity are related to each other through the spectral characteristics of the wave, and these relationships are unchanged. However, satellite observations of AGW parameters cannot always be explained within the framework of a single-frequency approach. This paper presents a two-frequency approach to the study of AGWs using the model of two coupled oscillators. It is shown that the perturbed movements of the elementary volume of the medium occur simultaneously at two natural frequencies. In this case, the connections between the wave fluctuations of the parameters are determined by the initial conditions, which can be arbitrary. Solutions in real functions for an isothermal atmosphere are obtained. The conditions under which single-frequency AGWs are obtained from the general two-frequency solution are investigated. The AGW waveforms measured from the satellite for velocities and displacements in single-frequency and dual-frequency modes are numerically simulated. The results of simulating two-frequency AGWs agree with the data of satellite measurements. Two-frequency AGWs are not always implemented at two different frequencies. It is shown that when the frequencies approach each other, the beat effect occurs and two closely related modes become indistinguishable. At the same wavelength, they have one center frequency and one phase velocity. The main feature of the two-frequency approach to the study of AGW is the expansion of the relationships between the wave parameters of the medium. This makes it possible to achieve satisfactory agreement of the model waveforms with the data of satellite measurements. Thus, the use of a two-frequency AGW treatment opens up new possibilities in the interpretation of experimental data.

Download Full-text

A Comparison between 3DVAR and EnKF for Data Assimilation Effects on the Yellow Sea Fog Forecast

10.20944/preprints201807.0577.v1 ◽

2018 ◽

Cited By ~ 3

Author(s):

Xiaoyu Gao ◽

Shanhong Gao ◽

Yue Yang

Keyword(s):

Data Assimilation ◽

Yellow Sea ◽

Initial Conditions ◽

Surface Wind ◽

Probability Of Detection ◽

The Other ◽

Moisture Distribution ◽

The Yellow Sea ◽

Background Error ◽

Sea Fog

The data assimilation method to improve sea fog forecast over the Yellow Sea is usually three-dimensional variational assimilation (3DVAR), whereas ensemble Kalman filter (EnKF) has not yet been applied on this weather phenomenon. In this paper, two sea fog cases over the Yellow sea, one spread widely and the other spread narrowly along the coastal area, are studied in detail by a series of numerical experiments with 3DVAR and EnKF based on the Grid-point Statistical Interpolation (GSI) system and the Weather Research and Forecasting (WRF) model. The results show that the assimilation effect of EnKF outperforms that of 3DVAR: for the widespread-fog case, the probability of detection and equitable threat scores of the forecasted sea fog area get improved respectively by ~57.9% and ~55.5%; the sea fog of the other case completely mis-forecasted by 3DVAR is produced successfully by EnKF. These improvements of EnKF relative to 3DVAR are benefited from its flow-dependent background error, resulting in more realistic depiction of sea surface wind for the widespread-fog case and better moisture distribution for the other case in the initial conditions. More importantly, the correlation between temperature and humidity in the background error of EnKF plays a vital role in the response of moisture to the assimilation of temperature, which leads to a great improvement on the initial moisture conditions for sea fog forecast.

Download Full-text

A dual-frequency approach for improving the accuracy of altimeter-measured sea surface wind speed

IGARSS 2000. IEEE 2000 International Geoscience and Remote Sensing Symposium. Taking the Pulse of the Planet: The Role of Remote Sensing in Managing the Environment. Proceedings (Cat. No.00CH37120) ◽

10.1109/igarss.2000.860378 ◽

2002 ◽

Author(s):

Ge Chen ◽

Chaoyang Fang ◽

Jianwen Ma ◽

Ping Xu

Keyword(s):

Wind Speed ◽

Surface Wind ◽

Surface Wind Speed ◽

Sea Surface ◽

Dual Frequency ◽

Sea Surface Wind Speed ◽

Sea Surface Wind

Download Full-text

Microwave Satellite Measurements for Coastal Area and Extreme Weather Monitoring

Remote Sensing ◽

10.3390/rs13163126 ◽

2021 ◽

Vol 13 (16) ◽

pp. 3126

Author(s):

Ferdinando Nunziata ◽

Xiaofeng Li ◽

Armando Marino ◽

Weizeng Shao ◽

Marcos Portabella ◽

...

Keyword(s):

Coastal Area ◽

Surface Wind ◽

European Space Agency ◽

Weather Conditions ◽

Extreme Weather ◽

Third Party ◽

Remotely Sensed Data ◽

Satellite Measurements ◽

Sea Surface Wind ◽

Space Agency

In this project report, the main outcomes relevant to the Sino-European Dragon-4 cooperation project ID 32235 “Microwave satellite measurements for coastal area and extreme weather monitoring” are reported. The project aimed at strengthening the Sino-European research cooperation in the exploitation of European Space Agency, Chinese and third-party mission Earth Observation (EO) microwave satellite data. The latter were exploited to perform an effective monitoring of coastal areas, even under extreme weather conditions. An integrated multifrequency/polarization approach based on complementary microwave sensors (e.g., Synthetic Aperture Radar, scatterometer, radiometer), together with ancillary information coming from independent sources, i.e., optical imagery, numerical simulations and ground measurements, was designed. In this framework, several tasks were addressed including marine target detection, sea pollution, sea surface wind estimation and coastline extraction/classification. The main outcomes are both theoretical (i.e., new models and algorithms were developed) and applicative (i.e., user-friendly maps were provided to the end-user community of coastal area management according to smart processing of remotely sensed data). The scientific relevance consists in the development of new algorithms, the effectiveness and robustness of which were verified on actual microwave measurements, and the improvement of existing methodologies to deal with challenging test cases.

Download Full-text