The role of horizontal resolution in simulating drivers of the global hydrological cycle

The role of atmospheric general circulation model (AGCM) horizontal resolution in representing the global energy budget and hydrological cycle is assessed, with the aim of improving the understanding of model uncertainties in simulating the hydrological cycle. We use two AGCMs from the UK Met Office Hadley Centre: HadGEM1-A at resolutions ranging from 270 to 60 km, and HadGEM3-A ranging from 135 to 25 km. The models exhibit a stable hydrological cycle, although too intense compared to reanalyses and observations. This over-intensity is explained by excess surface shortwave radiation, a common error in general circulation models (GCMs). This result is insensitive to resolution. However, as resolution is increased, precipitation decreases over the ocean and increases over the land. This is associated with an increase in atmospheric moisture transport from ocean to land, which changes the partitioning of moisture fluxes that contribute to precipitation over land from less local to more non-local moisture sources. The results start to converge at 60-km resolution, which underlines the excessive reliance of the mean hydrological cycle on physical parametrization (local unresolved processes) versus model dynamics (large-scale resolved processes) in coarser HadGEM1 and HadGEM3 GCMs. This finding may be valid for other GCMs, showing the necessity to analyze other chains of GCMs that may become available in the future with such a range of horizontal resolutions. Our finding supports the hypothesis that heterogeneity in model parametrization is one of the underlying causes of model disagreement in the Coupled Model Intercomparison Project (CMIP) exercises

Multispectral analysis of Northern Hemisphere temperature records over the last five millennia

Aiming to describe spatio-temporal climate variability on decadal-to-centennial time scales and longer, we analyzed a data set of 26 proxy records extending back 1,000–5,000 years; all records chosen were calibrated to yield temperatures. The seven irregularly sampled series in the data set were interpolated to a regular grid by optimized methods and then two advanced spectral methods—namely singular-spectrum analysis (SSA) and the continuous wavelet transform—were applied to individual series to separate significant oscillations from the high noise background. This univariate analysis identified several common periods across many of the 26 proxy records: a millennial trend, as well as oscillations of about 100 and 200 years, and a broad peak in the 40–70-year band. To study common NH oscillations, we then applied Multichannel SSA. Temperature variations on time scales longer than 600 years appear in our analysis as a dominant trend component, which shows climate features consistent with the Medieval Warm Period and the Little Ice Age. Statistically significant NH-wide peaks appear at 330, 250 and 110 years, as well as in a broad 50–80-year band. Strong variability centers in several bands are located around the North Atlantic basin and are in phase opposition between Greenland and Western Europe

Bilateral giant renal angiomyolipoma associated with hepatic lipoma in a patient with tuberous sclerosis Angiomiolipomas renais gigantes bilateralmente associados a lipoma hepático em pacientes com esclerose tuberosa

OBJECTIVE: To report a case of bilateral giant renal angiomyolipoma associated with tuberous sclerosis, with successful treatment, and to review the literature concerning angiomyolipoma treatment. CASE REPORT: Patient with tuberous sclerosis and angiomyolipoma diagnosed by ultrasonography during her pregnancy. At that time, the angiomyolipoma on the right side was 9 cm in diameter. Conservative management was selected during her pregnancy. The patient returned 7 years later, with a 24.7 x 19.2 x 10.7 cm tumor on the right side and another of 13 x 11.5 x 6.5 cm on the left side, in addition to multiple small angiomyolipomas. A nephron-sparing surgery with tumoral enucleation was performed on the right side, and after 3 months, the tumor on the left side was removed. Renal function in the post-operative period was preserved, and contrast medium progression was uniform and adequate in both kidneys. CONCLUSION: We conclude that an angiomyolipoma larger than 4 cm should be removed surgically, since they have a greater growth rate and pose a risk of hemorrhage. Resection of smaller tumors is safe and has decreased morbidity. Tumoral enucleation is an effective treatment method that preserves kidney function.<br>OBJETIVO: Relatar um caso de angiomiolipoma gigante, bilateral, associado a esclerose tuberosa, tratado com sucesso e revisar a literatura concernente ao tratamento do angiomiolipoma. RELATO DO CASO: Paciente portadora de esclerose tuberosa, com diagnóstico de angiomiolipoma realizado por ultra-sonografia durante gestação. O tumor apresentava 9cm de diâmetro, à direita. Optou-se por conduta conservadora durante a gestação, e a paciente retornou somente 7 anos após, com tumor de 24,7 x 19,2 x 10,7 cm à direita e outro à esquerda de 13 x 11,5 x 6,5 cm, além de múltiplos angiomiolipomas pequenos. Realizada inicialmente ressecção tumoral à direita, por enucleação, com preservação do parênquima renal, e 3 meses após à esquerda. A função renal pós-operatória se manteve inalterada, e ambos os rins apresentaram uniformidade e progressão do contraste adequados. CONCLUSÃO: Concluímos que os angiomiolipomas maiores que 4cm devem ser tratados cirurgicamente porque têm maior risco de crescimento e hemorragias. As ressecções de tumores menores são mais seguras e têm menor morbidade. A enucleação dos tumores é forma eficaz de ressecção dos mesmos, com preservação de parênquima renal