  This paper proposes a joint analysis of variations of global sea-level
pressure and of Earth's rotation (RP), expressed as the coordinates of the
rotation pole and length of day. Sea-Level-Pressure (SLP) extracted components
are a weak trend, eleven quasi-periodic or periodic components ($\sim$130, 90,
50, 22, 15, 4, 1.8 yr), an annual cycle and its first three harmonics. These
periods are characteristic of the space-time evolution of the Earth's rotation
axis and are present in many characteristic features of solar and terrestrial
physics. We focus mainly on the annual and to a lesser extent semi-annual
components. Maps of the first three components of SLP (that together comprise
more than 85% of the data variance) reveal interesting symmetries. The trend is
very stable and forms a triskel structure that can be modeled as Taylor-Couette
flow of mode 3. The annual component is characterized by a large negative
anomaly extending over Eurasia in the NH Summer (and the opposite in the NH
Winter) and three large positive anomalies over Australia and the southern tips
of South America and South Africa in the SH Spring (and the opposite in the SH
Autumn) forming a triskel. The semi-annual component is characterized by three
positive anomalies (an irregular triskel) in the NH Spring and Autumn (and the
opposite in the NH Summer and Winter), and in the SH Spring and Autumn by a
strong stable pattern consisting of three large negative anomalies forming a
clear triskel within the 40$^{\circ}$-60$^{\circ}$ annulus formed by the
southern oceans. A large positive anomaly centered over Antarctica, with its
maximum displaced toward Australia, and a smaller one centered over Southern
Africa complement the pattern.
