@article{fdi:010089662,
  title = {{A} new approach combining microwave heat pulse and infrared for non-invasive flow measurement},
  author = {{L}ouche, {H}. and {P}enarier, {A}. and {N}ouvel, {P}. and {C}lair, {B}. and {C}oillot, {C}. and {D}o, {F}r{\'e}d{\'e}ric},
  editor = {},
  language = {{ENG}},
  abstract = {{X}ylem sap flow measurement is a key method to quantify plant water use and assess the responses to environmental conditions and climatic change. {H}owever, available methods are generally invasive and of limited portability. {T}his paper presents a non-invasive approach called {TIMFLOW} that combines microwave heat pulse and infrared thermography, while having a high portability and versatility potential. {T}he methodology was tested in laboratory conditions for black poplar ({P}opulus nigra) stems of various diameters (10-45 mm) and for the known sap flow velocity range (10-100 cm h-1). {T}he heat pulse was generated by microwaves with a power amplifier supplying a bi-quad antenna at 2.45 {GH}z frequency located near the stem. {T}he scene was filmed using a relatively low-cost light and compact {I}nfra{R}ed ({IR}) thermography camera. {A} stem temperature map was used to determine the heat pulse propagation velocity. {T}he calculated heat velocity was highly correlated with the applied flow velocity with a unique relationship regardless of the diameter. {T}he latter result confirms the equation of {M}arshall (1958) which links the sap velocity to the heat velocity with a vessel fraction of around 25 % within samples. {T}he feasibility of outdoor measurements was also successfully tested. {T}he assumed potentials and limitations of the proposed methodology are discussed. {I}n summary, the study demonstrates the concept and validates, in woody stems, this new methodology for non-invasive portable sap flow velocity measurement.},
  keywords = {{M}icrowave self-heating ; {I}nfrared camera ; {H}eat wave ; {C}ontactless method ; {W}ater use},
  booktitle = {},
  journal = {{A}gricultural and {F}orest {M}eteorology},
  volume = {347},
  numero = {},
  pages = {109896 [9 ]},
  ISSN = {0168-1923},
  year = {2024},
  DOI = {10.1016/j.agrformet.2024.109896},
  URL = {https://www.documentation.ird.fr/hor/fdi:010089662},
}