Model OLD0: A Physical Parameterization for Clear-Sky Downward Longwave Radiation
Abstract Downward longwave irradiance DLF is one of the main components of the surface radiation balance (SRB), but its direct measurement is currently limited. Clouds modulate its behavior, and clear-sky DLF0 is predominant in composition of the final DLF value. It is shown that in mid-latitude and...
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Sociedade Brasileira de Meteorologia
2025-01-01
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| Series: | Revista Brasileira de Meteorologia |
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| author | Juan Carlos Ceballos Diego Pereira Enoré Jaidete Monteiro de Souza Francisco Luiz Leitão de Mesquita |
| author_facet | Juan Carlos Ceballos Diego Pereira Enoré Jaidete Monteiro de Souza Francisco Luiz Leitão de Mesquita |
| author_sort | Juan Carlos Ceballos |
| collection | DOAJ |
| description | Abstract Downward longwave irradiance DLF is one of the main components of the surface radiation balance (SRB), but its direct measurement is currently limited. Clouds modulate its behavior, and clear-sky DLF0 is predominant in composition of the final DLF value. It is shown that in mid-latitude and tropical atmospheres, DLF0 can be represented as the sum of fluxes from three distinct spectral regions: R1 (λ < 7.5 µm), R2 (7.5 to 14 µm), and R3 (λ > 14 µm). R1 and R3 are closely described by blackbody radiation at screen temperature (Tscr), while R2 exhibits a mean emissivity that primarily depends on total precipitable water (w). It is presented a simple yet consistent physically-based model (hereafter denoted by OLD0), suitable for estimation of DLF0 at ground level. Validation of OLD0 with ground-based data of a worldwide set of 21 stations shows fair accuracy with bias MBE lower than 6 W.m-2 and spread (standard deviation STD) lower than 12 W.m-2 for typical values DLF0 ~ 300-400 W.m-2, compatible with surface pyrgeometer measures. The proposed algorithm outperforms existing methods, achieving a mean bias error (in module |MBE|) of approximately 2.8 W.m-2. In contrast, other widely used algorithms typically exhibit |MBEs| ranging from 8.1 to 15.9 W.m-2. |
| format | Article |
| id | doaj-art-cb99845d5def42eb9452c1c2ab7e2a31 |
| institution | Kabale University |
| issn | 1982-4351 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Sociedade Brasileira de Meteorologia |
| record_format | Article |
| series | Revista Brasileira de Meteorologia |
| spelling | doaj-art-cb99845d5def42eb9452c1c2ab7e2a312025-02-04T07:37:05ZengSociedade Brasileira de MeteorologiaRevista Brasileira de Meteorologia1982-43512025-01-014010.1590/0102-77864010033bModel OLD0: A Physical Parameterization for Clear-Sky Downward Longwave RadiationJuan Carlos CeballosDiego Pereira Enoréhttps://orcid.org/0000-0001-7001-0560Jaidete Monteiro de SouzaFrancisco Luiz Leitão de MesquitaAbstract Downward longwave irradiance DLF is one of the main components of the surface radiation balance (SRB), but its direct measurement is currently limited. Clouds modulate its behavior, and clear-sky DLF0 is predominant in composition of the final DLF value. It is shown that in mid-latitude and tropical atmospheres, DLF0 can be represented as the sum of fluxes from three distinct spectral regions: R1 (λ < 7.5 µm), R2 (7.5 to 14 µm), and R3 (λ > 14 µm). R1 and R3 are closely described by blackbody radiation at screen temperature (Tscr), while R2 exhibits a mean emissivity that primarily depends on total precipitable water (w). It is presented a simple yet consistent physically-based model (hereafter denoted by OLD0), suitable for estimation of DLF0 at ground level. Validation of OLD0 with ground-based data of a worldwide set of 21 stations shows fair accuracy with bias MBE lower than 6 W.m-2 and spread (standard deviation STD) lower than 12 W.m-2 for typical values DLF0 ~ 300-400 W.m-2, compatible with surface pyrgeometer measures. The proposed algorithm outperforms existing methods, achieving a mean bias error (in module |MBE|) of approximately 2.8 W.m-2. In contrast, other widely used algorithms typically exhibit |MBEs| ranging from 8.1 to 15.9 W.m-2.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-77862025000100200&lng=en&tlng=endownward longwave radiationclear sky radiationatmospheric longwave modelmodel OLD0 |
| spellingShingle | Juan Carlos Ceballos Diego Pereira Enoré Jaidete Monteiro de Souza Francisco Luiz Leitão de Mesquita Model OLD0: A Physical Parameterization for Clear-Sky Downward Longwave Radiation Revista Brasileira de Meteorologia downward longwave radiation clear sky radiation atmospheric longwave model model OLD0 |
| title | Model OLD0: A Physical Parameterization for Clear-Sky Downward Longwave Radiation |
| title_full | Model OLD0: A Physical Parameterization for Clear-Sky Downward Longwave Radiation |
| title_fullStr | Model OLD0: A Physical Parameterization for Clear-Sky Downward Longwave Radiation |
| title_full_unstemmed | Model OLD0: A Physical Parameterization for Clear-Sky Downward Longwave Radiation |
| title_short | Model OLD0: A Physical Parameterization for Clear-Sky Downward Longwave Radiation |
| title_sort | model old0 a physical parameterization for clear sky downward longwave radiation |
| topic | downward longwave radiation clear sky radiation atmospheric longwave model model OLD0 |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-77862025000100200&lng=en&tlng=en |
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