Impact of humidity biases on light precipitation occurrence: observations versus simulations
<p>This work uses a network of GPS stations over Europe from which a homogenized integrated water vapor (IWV) dataset has been retrieved, completed with colocated temperature and precipitation measurements over specific stations to (i) estimate the biases of six regional climate models over Eu...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2019-02-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/19/1471/2019/acp-19-1471-2019.pdf |
| _version_ | 1819291551934709760 |
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| author | S. Bastin P. Drobinski M. Chiriaco O. Bock R. Roehrig C. Gallardo D. Conte M. Domínguez Alonso M. Domínguez Alonso L. Li P. Lionello P. Lionello A. C. Parracho A. C. Parracho |
| author_facet | S. Bastin P. Drobinski M. Chiriaco O. Bock R. Roehrig C. Gallardo D. Conte M. Domínguez Alonso M. Domínguez Alonso L. Li P. Lionello P. Lionello A. C. Parracho A. C. Parracho |
| author_sort | S. Bastin |
| collection | DOAJ |
| description | <p>This work uses a network of GPS stations over Europe from which a homogenized
integrated water vapor (IWV) dataset has been retrieved, completed with
colocated temperature and precipitation measurements over specific stations
to (i) estimate the biases of six regional climate models over Europe in terms
of humidity; (ii) understand their origins; and (iii) finally assess the impact
of these biases on the frequency of occurrence of precipitation. The
evaluated simulations have been performed in the framework of
HYMEX/Med-CORDEX programs and cover the Mediterranean area and part of Europe
at horizontal resolutions of 50 to 12 km.</p>
<p>The analysis shows that models tend to overestimate the low values of IWV
and the use of the nudging technique reduces the differences between GPS and
simulated IWV. Results suggest that physics of models mostly explain the
mean biases, while dynamics affects the variability. The land
surface–atmosphere exchanges affect the estimation of IWV over most part of
Europe, especially in summer. The limitations of the models to represent
these processes explain part of their biases in IWV. However, models
correctly simulate the dependance between IWV and temperature, and
specifically the deviation that this relationship experiences regarding the
Clausius–Clapeyron law after a critical value of temperature (<span class="inline-formula"><i>T</i><sub>break</sub></span>).
The high spatial variability of <span class="inline-formula"><i>T</i><sub>break</sub></span> indicates that it has a strong
dependence on local processes which drive the local humidity sources. This
explains why the maximum values of IWV are not necessarily observed over
warmer areas, which are often dry areas.</p>
<p>Finally, it is shown over the SIRTA observatory (near Paris) that the frequency
of occurrence of light precipitation is strongly conditioned by the biases
in IWV and by the precision of the models to reproduce the distribution of
IWV as a function of the temperature. The results of the models indicate
that a similar dependence occurs in other areas of Europe, especially where
precipitation has a predominantly convective character. According to the
observations, for each range of temperature, there is a critical value of
IWV from which precipitation starts to increase. The critical values and the
probability of exceeding them are simulated with a bias that depends on the
model. Those models, which generally present light precipitation too often,
show lower critical values and higher probability of exceeding them.</p> |
| first_indexed | 2024-12-24T03:40:27Z |
| format | Article |
| id | doaj.art-db249d4e425c49048940dd02bb70128a |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-24T03:40:27Z |
| publishDate | 2019-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-db249d4e425c49048940dd02bb70128a2022-12-21T17:16:56ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242019-02-01191471149010.5194/acp-19-1471-2019Impact of humidity biases on light precipitation occurrence: observations versus simulationsS. Bastin0P. Drobinski1M. Chiriaco2O. Bock3R. Roehrig4C. Gallardo5D. Conte6M. Domínguez Alonso7M. Domínguez Alonso8L. Li9P. Lionello10P. Lionello11A. C. Parracho12A. C. Parracho13LATMOS/IPSL, UVSQ Université Paris-Saclay, Sorbonne Université, CNRS, Guyancourt, FranceLMD/IPSL, Ecole Polytechnique, Sorbonne Université, ENS, CNRS, Palaiseau, FranceLATMOS/IPSL, UVSQ Université Paris-Saclay, Sorbonne Université, CNRS, Guyancourt, FranceIPGP, IGN, ENSG, Université Paris Diderot, Sorbonne Paris Cité, UMR7154 CNRS, Paris, FranceCNRM, Université de Toulouse, Meteo-France, CNRS, Toulouse, FranceUCLM, Instituto de Ciencias Ambientales, Toledo, SpainAEMET, Agencia Estatal de Meteorología, Madrid, SpainUCLM, Instituto de Ciencias Ambientales, Toledo, SpainAEMET, Agencia Estatal de Meteorología, Madrid, SpainLMD/IPSL, Ecole Polytechnique, Sorbonne Université, ENS, CNRS, Palaiseau, FranceCMCC, Euro Mediterranean Center on Climage Change, 73100 Lecce, ItalyDiSTeBA, University of Salento, 73100 Lecce, ItalyLATMOS/IPSL, UVSQ Université Paris-Saclay, Sorbonne Université, CNRS, Guyancourt, FranceIPGP, IGN, ENSG, Université Paris Diderot, Sorbonne Paris Cité, UMR7154 CNRS, Paris, France<p>This work uses a network of GPS stations over Europe from which a homogenized integrated water vapor (IWV) dataset has been retrieved, completed with colocated temperature and precipitation measurements over specific stations to (i) estimate the biases of six regional climate models over Europe in terms of humidity; (ii) understand their origins; and (iii) finally assess the impact of these biases on the frequency of occurrence of precipitation. The evaluated simulations have been performed in the framework of HYMEX/Med-CORDEX programs and cover the Mediterranean area and part of Europe at horizontal resolutions of 50 to 12 km.</p> <p>The analysis shows that models tend to overestimate the low values of IWV and the use of the nudging technique reduces the differences between GPS and simulated IWV. Results suggest that physics of models mostly explain the mean biases, while dynamics affects the variability. The land surface–atmosphere exchanges affect the estimation of IWV over most part of Europe, especially in summer. The limitations of the models to represent these processes explain part of their biases in IWV. However, models correctly simulate the dependance between IWV and temperature, and specifically the deviation that this relationship experiences regarding the Clausius–Clapeyron law after a critical value of temperature (<span class="inline-formula"><i>T</i><sub>break</sub></span>). The high spatial variability of <span class="inline-formula"><i>T</i><sub>break</sub></span> indicates that it has a strong dependence on local processes which drive the local humidity sources. This explains why the maximum values of IWV are not necessarily observed over warmer areas, which are often dry areas.</p> <p>Finally, it is shown over the SIRTA observatory (near Paris) that the frequency of occurrence of light precipitation is strongly conditioned by the biases in IWV and by the precision of the models to reproduce the distribution of IWV as a function of the temperature. The results of the models indicate that a similar dependence occurs in other areas of Europe, especially where precipitation has a predominantly convective character. According to the observations, for each range of temperature, there is a critical value of IWV from which precipitation starts to increase. The critical values and the probability of exceeding them are simulated with a bias that depends on the model. Those models, which generally present light precipitation too often, show lower critical values and higher probability of exceeding them.</p>https://www.atmos-chem-phys.net/19/1471/2019/acp-19-1471-2019.pdf |
| spellingShingle | S. Bastin P. Drobinski M. Chiriaco O. Bock R. Roehrig C. Gallardo D. Conte M. Domínguez Alonso M. Domínguez Alonso L. Li P. Lionello P. Lionello A. C. Parracho A. C. Parracho Impact of humidity biases on light precipitation occurrence: observations versus simulations Atmospheric Chemistry and Physics |
| title | Impact of humidity biases on light precipitation occurrence: observations versus simulations |
| title_full | Impact of humidity biases on light precipitation occurrence: observations versus simulations |
| title_fullStr | Impact of humidity biases on light precipitation occurrence: observations versus simulations |
| title_full_unstemmed | Impact of humidity biases on light precipitation occurrence: observations versus simulations |
| title_short | Impact of humidity biases on light precipitation occurrence: observations versus simulations |
| title_sort | impact of humidity biases on light precipitation occurrence observations versus simulations |
| url | https://www.atmos-chem-phys.net/19/1471/2019/acp-19-1471-2019.pdf |
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