4. Precipitation#
Note
This chapter is based on the chapter Precipitation from the lecture notes Water Quantity and Quality by K. Metselaar et al., Wageningen University, 2022. The first section of this chapter is based on a book chapter by Uijlenhoet (2008).
Fig. 4.1 Rainfall in the Netherlands – photo from (KNMI, 2024).#
Nomenclature
Symbol |
Quantity |
Quantity name in Dutch |
Dimension |
Widely used unit (if not SI) |
|---|---|---|---|---|
\(A_a\) |
Correction for wet antennas |
Correctie voor natte antennes |
[dB] |
|
\(A_j\) |
Sub-area of the catchement |
Deelgebieden in het stroomgebied |
[L\(^2\)] |
|
\(a\) |
Z-R coefficient |
Z-R coëfficiënt |
Dependent on the value of b |
|
\(C\) |
Radar constant |
Radar constante |
[T\(^3\)/ML] |
|
\(b\) |
Z-R coefficient |
Z-R coefficient |
[-] |
|
\(e^* (T)\) |
Saturation vapor pressure |
Verzadigingsdampdruk |
[M/LT\(^{2}\)] |
[hPa] |
\(L\) |
Link length |
Lengte van de link |
[L] |
[km] |
\(N\) |
Number of stations |
Aantal stations |
[-] |
|
\(P\) |
Received power |
Ontvangen vermogen |
[ML\(^2\)/T\(^3\)] |
[dBm] |
\(P_{max}\) |
Maximum received power |
Maximaal ontvangen vermogen |
[ML\(^2\)/T\(^3\)] |
[dBm] |
\(P_{min}\) |
Minimum received power |
Minimaal ontvangen vermogen |
[ML\(^2\)/T\(^3\)] |
[dBm] |
\(P_r\) |
Received power |
Ontvangen vermogen |
[ML\(^2\)/T\(^3\)] |
|
\(P_{ref}\) |
Reference received power (in absence of rain) |
Referentie ontvangen vermogen (in afwezigheid van regen) |
[ML\(^2\)/T\(^3\)] |
[dBm] |
\(R\) |
Rainfall depth |
Regenhoeveelheid |
[L] |
[mm] |
\(R\) |
Rainfall intensity |
Regenintensiteit |
[L/T] |
[mm/h] |
\(\overline{R}\) |
Average rainfall |
Gemiddelde regenval |
[L/T] |
[mm/h] |
\(R_j\) |
Rainfall per rain gauge |
Regenval per regenmeter |
[L/T] |
[mm/h] |
\(R_X\) |
Rainfall at station X |
Regenval bij station X |
[L/T] |
[mm/h] |
\(r\) |
Distance to the radar |
Afstand tot de radar |
[L] |
|
\(r_{station}\) |
Distance to station X |
Afstand tot station X |
[L] |
|
\(T\) |
Temperature |
Temperatuur |
[\(^{\circ}\)C] |
|
\(Z\) |
Radar reflectivity factor |
Reflectiviteitsfactor van de radar |
[L\(^6\)/L\(^3\)] |
[mm\(^6\)/m\(^3\)] |
\(\alpha\) |
Factor to distribute the relative contributions of the minimum and maximum received power |
Factor om de relatieve bijdragen van het minimum en maximum ontvangen vermogen te bepalen |
[-] |
|
\(\gamma (d)\) |
Semivariance of rainfall at distance d |
Semivariantie van regenval op afstand d |
[L\(^2\)/T\(^2\)] |
[mm\(^2\)/h\(^2\)] |
\(\omega_j\) |
Weight per station (for computing the average) |
Gewicht per station (voor berekenen van het gemiddelde) |
[-] |
Note
In this chapter, the symbol \(P\) represents power, whereas it is commonly used to denote precipitation.