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PREC-TRADE-CYCLE.
1 June 2020 - 31 May 2023.

General info on the project

Research questions
  • Which factors trigger precipitation in trade wind cumulus clouds and under which conditions, e.g. wind, turbulence, humidity, and aerosols?
  • Are models capable of producing rain under the same observed conditions?
  • How does precipitation affect the environment?
Objectives
  1. Characterization of warm precipitation processes based on observations analyzing the main dynamic and thermodynamic factors and assessment of the driving parameters for precipitation development in trade wind cumuli.
  2. Evaluation of precipitation processes in LES with observations: assessment of the main factors influencing precipitation formation in LES with emphasis on autoconversion parametrization.
  3. Assessment of the vertical structure of the evaporation rate of precipitation and its dependency on atmospheric parameters and DSD.

The dataset

W-band radar quicklooks, ship trajectory, cloud fraction profiles during the Maria S. Merian cruise within EUREC4A

Browse through the menu in the grey bar to see what we saw :) Here's how it works.They grey  bar contains the settings to choose, from left to right:

  • number of panels: set here the number of panels you want to check, from 1 to 4)
  • site: MSMerian: the ship we were on,
  • variable to show in the top left panel
  • variable to show in the bottom left panel
  • date: select the day of the campaign you want to see, ranging from 18 jan to 19 Feb we have been at sea.
  • variable to show in the top right panel
  • variable to show in the bottom right panel

What  can you see? here's the list of the variables with an small explanation:

  •  reflectivity: this variable is proportional to the number concentration of drops in the cloud, and to the sixth power of the drops diameter. It gives an idea of the amount and dimension of the drops in the radar volume. When it is large, for example larger than 20 dB, you are looking at rain showers. When it is smaller than -20 dB, those are puffy cumulus clouds.
  • Mean Doppler velocity: it is the mean vertical velocity of all drops contained in the radar volume. it is affected by air motion. When positive, the drops in the radar volume go up, otherwise, for example when it rains, they go down.
  • spectral width: This variable measures somehow the turbulence in the cloud. When it is very large, it is because of turbulence or of hydrometeors of very different size that mix together.
  • skewness; This variable in the cloud can measure the stage of development of the precipitation. When negative rain starts to form, when positive, rain dominates the signal.
  • meteo station: this plot shows Pressure, air temperature, relative humidity and horizontal wind speed at the radar height.
  • cloud fraction profiles and hourly plots: they show the percentage of cloudiness observed over a fixed time interval.