bridget.sap_flow._sap_velocity_East30_3needle

bridget.sap_flow._sap_velocity_East30_3needle(dTu, dTd, ru=0.006, rd=0.006, **kwargs)[source]

Sap velocity for East30 Sensor

Calculate sap velocity for East30 3-needle sap flow sensors for two corresponding temperature measurements below and above the middle heater needle. Sap velocity (equation (6) page 33 East30 3-needle sap flow sensor manual), last term omitted, in [m/s]

Parameters

  • ru (float) – distance from heater to sensor, upstream (ru) and downstream (rd), in [m] (upstream corresponds to the needle below the heater, downstream in above the heater, in an assumed upward water movement)

  • rd (float) – distance from heater to sensor, upstream (ru) and downstream (rd), in [m] (upstream corresponds to the needle below the heater, downstream in above the heater, in an assumed upward water movement)

  • dTu (list, numpy.array) – time series of temperature differences in [K] at the upstream thermistor (below the heater in an upward water movement), differences are between initial temperature and 60 seconds after heating.

  • dTd (list, numpy.array) – time series of temperature differences in [K] at the downstream thermistor (above the heater in an upward water movement), differences are between initial temperature and 60 seconds after heating.

Keyword Arguments

  • k_sapwood (float) – thermal conductivity of sapwood in [W m-1 K-1], 0.5 is a literature value

  • Cw (float) – specific heat of water in [J m-3 K-1], 4.1796 J/(cm³ K) at 25°C is a literature value

  • force_si (bool) – Defaults to False.

Returns

vs – Array of sap velocity, here converted to [cm h-1].

Return type

numpy.array

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