# Precipitation measurements on board the RV-Meteor for cruise M161 EUREC4A field campaign and the transit across the Atlantic 14.01.2020 - 29.02.2020

* retrieved by the Bordwetterwarte of the German weather service (DWD)
* for non commercial use only
* file: 20200114_M161_Nsl.CSV contains information about precipitation (Niederschlag = Nsl)
* Info from Holger Jens DWD

## German version:
**Anmerkung:**
Wir verwenden mehrere Sensoren an Bord, der SRM ( Schiffsregenmesser ) liefert noch brauchbare Ergebnisse in den Summen,
der Radarsensor WS100 ist eigentlich nur für das Ereignis oder Art des Niederschlages zu gebrauchen, die Mengen stimmen dort nicht mehr.
Es ist sowieso problematisch an Bord eines Schiffes, vernünftig Niederschlagssummen zu erfassen.

Für die Niederschlagserfassung werden an Bord Fs Meteor - Schiffsregenmesser SRM450 nach Prof. Hasse ( Fa. Eigenbrodt),
- Niederschlagswächter (Thies),
- Radarsensor WS100-UMB (Lufft)
verwendet ( Stand März 2020 ).

Die Aufzeichnung erfolgt im ASCII-Format, wobei die Daten eine feste Breite haben und untereinander durch ein Semikolon getrennt sind (CSV-Format). Führende Nullen werden
durch Leerzeichen ersetzt. Als Dezimaltrennzeichen wird ein Punkt verwendet. Die Niederschlagsdaten werden immer im 1-Minuten-Intervall aufgezeichnet.
Die erste Zeile einer jeden Datendatei enthält die durch Semikolon getrennten Bezeichnungen der gespeicherten Messwerte.

## English version:
**Note:**
We use several sensors on board, the SRM ( ship rain gauge ) still provides useful results in the totals,
the radar sensor WS100 is actually only usable for the event or type of precipitation, the amounts here are not correct anymore.
It is generally problematic to capture reasonable precipitation totals on board of a ship.

For the precipitation registration on board RV Meteor - ship rain gauge SRM450 after Prof. Hasse (Fa. Eigenbrodt),
- Precipitation monitor (Thies),
- radar sensor WS100-UMB (Lufft)
are used ( March 2020 ).

The recording is done in ASCII format, where the data have a fixed width and are separated from each other by a semicolon (CSV format). Leading zeros are replaced by blanks. A point is used as decimal separator. Precipitation data are always recorded at 1-minute intervals.
The first line of each data file contains the names of the stored measured values separated by semicolons.

## Precipitation data description
| ***Header***    | **Meaning and unit**                                      |
| :-------------- | :-------------------------------------------------------- |
| *Timestamp*     | Date and time in the format DD.MM.YYY hh:mm               |
| *Long*          | Geographic longitude in decimal format                    |
| *Lat*           | Geographic Latitude in decimal format                     |
| *RR_SRM*        | Rain intensity of the ship's rain gauge in mm/h           |
| *st_RR_SRM*     | Status of rain intensity                                  |
| *Dauer*         | Rain duration in sec.                                     |
| *Tro1*          | Drop counter1 up                                          |
| *st_Tro1*       | Status drop counter1 up                                   |
| *Tro2*          | Drop counter2 up                                          |
| *st_Tro2*       | Status drop counter2 up                                   |
| *Trs*           | side drop counter                                         |
| *st_Trs*        | Status side drop counter                                  |
| *FF*            | Wind speed at rain gauge in m/s                           |
| *DD*            | Wind direction in degrees                                 |
| *TT*            | Air temperature in °C                                     |
| *RH*            | relative humidity in                                      |
| *VVV*           | Visibility in m                                           |
| *RR_WS100_h*    | Rain intensity of the radar sensor in mm/h                |
| *st_RR_WS100_h* | Status rain intensity of the radar sensor                 |
| *RR_WS100_m*    | Rain intensity of the radar sensor in mm/min              |
| *NType_WS100*   | Precipitation type of the radar sensor                    |
| *Nabs_WS100*    | cumulative precipitation amount of the radar sensor in mm |


some more information:
- there was a WS100 installed, more info -> https://www.lufft.com/de-de/produkte/niederschlags-sensoren-304/ws100-radar-niederschlagssensor-intelligenter-disdrometer-2360/
- additionally a SRM was also installed -> https://www.eigenbrodt.de/en/products/meteorologie/ship-rain-gauge-srm-450/
- the time resolution of the file is 1 minute
- there is a column "Dauer" which tracks how many seconds it rained during that 1 minute
- RR_WS100_h is the rain rate in mm/h
- RR_WS100_m is probably rain rate in mm/min
- NTyp_WS100 is the type of precipitation (60=liquid rain), more info page 23, https://www.lufft.com/de-de/produkte/download-de/bedienanleitung-lufft-wsxxx-umb-wettersensoren-de/
- Nabs_WS100 is the absolute ammount of precip since the last restart of the system in mm