@article{fdi:010077791,
  title = {{R}adar remote sensing of precipitation in high mountains : detection and characterization of melting layer in the {G}renoble {V}alley, {F}rench {A}lps},
  author = {{K}hanal, {A}. {K}. and {D}elrieu, {G}. and {C}azenave, {F}r{\'e}d{\'e}ric and {B}oudevillain, {B}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he {R}ad{A}lp experiment aims at developing advanced methods for rain and snow estimation using weather radar remote sensing techniques in high mountain regions for improved water resource assessment and hydrological risk mitigation. {A} unique observation system has been deployed in the {F}rench {A}lps, {G}renoble region. {I}t is composed of a {M}eteo-{F}rance operated {X}-band {MOUC} radar (volumetric, {D}oppler and polarimetric) on top of the {M}t {M}oucherotte (1920 m {ASL}), the {X}-band {XPORT} research radar (volumetric, {D}oppler, polarimetric), a {K}-band micro rain radar ({MRR}, {D}oppler, vertically pointing) and in situ sensors (rain gauges, disdrometers), latter three operated on the {G}renoble campus (220 m {ASL}). {B}ased on the observation that the precipitation phase changes at/below the elevation of mountain-top {MOUC} radar for more than 60% of the significant events, an algorithm for {ML} identification has been developed using valley-based radar systems: it uses the quasi vertical profiles of {XPORT} polarimetric measurements (horizontal and vertical reflectivity, differential reflectivity, cross-polar correlation coefficient) and the {MRR} vertical profiles of apparent falling velocity spectra. {T}he algorithm produces time series of the altitudes and values of peaks and inflection points of the different radar observables. {A} literature review allows us to link the micro-physical processes at play during the melting process with the available polarimetric and {D}oppler signatures, e.g., (i) regarding the altitude differences between the peaks of reflectivity, cross-polar correlation coefficient and differential reflectivity, as well as (ii) regarding the co-variation of the profiles of {D}oppler velocity spectra and cross-polar correlation coefficient. {A} statistical analysis of the {ML} based on 42 rain events (98 h of {XPORT} data) is then proposed. {A}mong other results, this study indicates that (i) the mean value of the {ML} width in {G}renoble is 610 m with a standard deviation of 160 m; (ii) the mean altitude difference between the horizontal reflectivity and the rho {HV} peaks is 90 m and the mean altitude difference between the rho {HV} and {Z}dr peaks is 30 m; (iii) even for the limited rainrate range in the dataset (0-8.5 mm h-1), the "intensity effect" is clear on the reflectivity profile and the {ML} width, as well as on polarimetric variables such as rho {HV} peak value and the {Z}dr enhancement in the upper part of the profile. {O}n the contrary, the study of both the "density effect" and the influence of the 0 degrees {C} isotherm altitude did not yield significant results with the considered dataset; (iv) a principal component analysis on one hand shows the richness of the dataset since the first 2 {PC}s explain only 50% of the total variance and on the other hand the added-value of the polarimetric variables since they rank high in a ranking of the total variance explained by individual variables.},
  keywords = {melting layer ; radar remote sensing ; hydro-meteorology ; high mountains ; {A}lps ; {FRANCE} ; {ALPES} ; {GRENOBLE} {VALLEE}},
  booktitle = {},
  journal = {{A}tmosphere},
  volume = {10},
  numero = {12},
  pages = {784 [22 ]},
  year = {2019},
  DOI = {10.3390/atmos10120784},
  URL = {https://www.documentation.ird.fr/hor/fdi:010077791},
}