Assessment and Error Analysis of Terra‐MODIS and MISR Cloud‐Top Heights Through Comparison With ISS‐CATS Lidar

Mitra, Arka; Girolamo, Larry Di; Hong, Yulan; Zhan, Yizhe; Mueller, K. J.

doi:10.1029/2020jd034281

Cited by 20 publications

(62 citation statements)

References 46 publications

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“…To ensure that our algorithm is applied on scenes with well-separated cloud layers, we choose only those scenes where MODIS-MISR CTH difference > 1 km [suggestive of well-separated cloud layers, based on Mitra et., al (2021)]. Upon imposing these conditions, it is found that all scenes in the remaining dataset are indeed multi-layered according to CATS.…”

Section: Datamentioning

confidence: 99%

“…[detailed in (Mitra et al, 2021)]. These estimates of high cloud 𝜏 𝑉𝐼𝑆 are converted to infrared effective emissivity (𝐴 𝑐 𝜖 𝑐 , assuming 𝐴 𝑐 = 1) using Eq.…”

Section: Datamentioning

confidence: 99%

“…This aforementioned modification to the CO2-slicing is rooted in physical theory and makes use of Terra's unique design for fusion between instruments, which allows us to improve the MODIS upper-layer CTP/CTH and emissivity, provided the layer is optically thin for MISR to retrieve CTH of the lower cloud [this is also the regime where MODIS CO2-slicing CTH errors are maximum (Mitra et al, 2021)]. To distinguish the new high cloud properties from the operational MODIS data variables, we shall refer to the new estimates of cirrus CTP/CTH, 𝐴 𝑐 𝜖 𝑐 and 𝜏 𝑉𝐼𝑆 as the MISR-MODIS Fusion Product for Cloud-Top Height (MM_CTH).…”

Section: Implementation Of the 2-layered Co2-slicingmentioning

confidence: 99%

“…By far the most dominant multi-layered cloud regime is a 2-layered system with thin cirrus overlying water clouds, followed by thin cirrus overlying mixed-phase clouds (Wang & Dessler, 2006;Oreopoulos et al, 2017;Hong and Di Girolamo 2020). Numerous validation studies against ground and space-based active sensors have shown that the presence of optically thin cirrus overlying low clouds leads to the most significant disagreements in retrieved CTH between MISR and MODIS (Naud et al, 2007;Marchand et al, 2010;Mitra et al, 2021), suggestive of the presence of independent information of the upper and lower cloud layers in the two datasets.…”

Section: Introductionmentioning

confidence: 99%

“…The path to improving the Terra record relies on exploiting the distinctiveness of the MODIS and MISR CTH techniques to estimate the properties of multi-layered clouds more accurately, as previously suggested (Naud et al, 2007;Mitra et al, 2021). CTH errors in multi-layered cloud regimes have been comprehensively studied for the Terra MODIS and MISR records by Mitra et al (2021) using collocated Cloud-Aerosol Transport System (CATS) lidar observations (McGill et al, 2015;Yorks et al, 2016) that operated aboard the International Space Station (ISS) from 2015-2017. Comparison of MODIS Collection 6.1 CTH with CATS showed that the CTHs of thin cirrus in these multi-layered regimes were underestimated by more than 1 km on average.…”

Section: Introductionmentioning

confidence: 99%

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Fusion of MISR Stereo Cloud Heights and Terra-MODIS Thermal Infrared Radiances to Estimate Multi-layered Cloud Properties

Mitra

Loveridge

Girolamo

2022

Preprint

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Our longest, stable record of cloud-top pressure (CTP) and cloud-top height (CTH) are derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Multi-Angle Imaging Spectroradiometer (MISR) on Terra. Because of single cloudlayer assumptions in their standard algorithms, they provide only single CTP/CTH retrievals in multi-layered situations. In the predominant multi-layered regime of thin cirrus over low clouds, MODIS significantly overestimates cirrus CTP and emissivity, while MISR accurately retrieves low-cloud CTH. Utilizing these complementary capabilities, we develop a retrieval algorithm for accurately determining both-layer CTP and cirrus emissivity for such 2-layered clouds, by applying the MISR low-cloud CTH as a boundary condition to a modified MODIS CO 2 -slicing retrieval.We evaluate our 2-layered retrievals against collocated Cloud-Aerosol Transport System (CATS) lidar observations. Relative to CATS, the mean bias of the upper cloud CTP and emissivity are reduced by ˜90% and ˜75% respectively in the new technique, compared to standard MODIS products. We develop an error model for the 2-layered retrieval accounting for systematic and random errors. We find up to 88% of all residuals lie within modeled 95% confidence intervals, indicating a near-closure of error budget. This reduction in error leads to a reduction in modeled atmospheric longwave radiative flux biases ranging between 5-40 Wm -2 , depending on the position and optical properties of the layers. Given this large radiative impact, we recommend that the pixel-level 2-layered MODIS+MISR fusion algorithm be applied over the entire MISR swath for the 22-year Terra record, leading to a first-of-its-kind 2-layered cloud climatology from Terra's morning orbit.

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Section: Datamentioning

confidence: 99%

“…[detailed in (Mitra et al, 2021)]. These estimates of high cloud 𝜏 𝑉𝐼𝑆 are converted to infrared effective emissivity (𝐴 𝑐 𝜖 𝑐 , assuming 𝐴 𝑐 = 1) using Eq.…”

Section: Datamentioning

confidence: 99%

Section: Implementation Of the 2-layered Co2-slicingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Fusion of MISR Stereo Cloud Heights and Terra-MODIS Thermal Infrared Radiances to Estimate Multi-layered Cloud Properties

Mitra

Loveridge

Girolamo

2022

Preprint

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Lessons Learned from the Updated GEWEX Cloud Assessment Database

Stubenrauch,

Kinne,

Mandorli

et al. 2024

Surv Geophys

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Since the first Global Energy and Water Exchanges cloud assessment a decade ago, existing cloud property retrievals have been revised and new retrievals have been developed. The new global long-term cloud datasets show, in general, similar results to those of the previous assessment. A notable exception is the reduced cloud amount provided by the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) Science Team, resulting from an improved aerosol–cloud distinction. Height, opacity and thermodynamic phase determine the radiative effect of clouds. Their distributions as well as relative occurrences of cloud types distinguished by height and optical depth are discussed. The similar results of the two assessments indicate that further improvement, in particular on vertical cloud layering, can only be achieved by combining complementary information. We suggest such combination methods to estimate the amount of all clouds within the atmospheric column, including those hidden by clouds aloft. The results compare well with those from CloudSat-CALIPSO radar–lidar geometrical profiles as well as with results from the International Satellite Cloud Climatology Project (ISCCP) corrected by the cloud vertical layer model, which is used for the computation of the ISCCP-derived radiative fluxes. Furthermore, we highlight studies on cloud monitoring using the information from the histograms of the database and give guidelines for: (1) the use of satellite-retrieved cloud properties in climate studies and climate model evaluation and (2) improved retrieval strategies.

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